Does anything change if Opportunity Attacks only allow you to make melee weapon attacks?

Inspired from discussions regarding Whirlwind Attack and also this answer to this Q/A (“Can I use the War Caster feat to cast Vampiric Touch as a reaction?”) which mentions using a previously cast (currently concentrated on) vampiric touch to make opportunity attacks without the War Caster feat.

The “Opportunity Attack” section states:

You can make an opportunity attack when a hostile creature that you can see moves out of your reach. To make the opportunity attack, you use your reaction to make one melee attack against the provoking creature.

Would changing the bolded text to instead read “melee weapon attack” have any affects whatsoever?

Using a ranged weapon with the Ammunition property for a melee attack

Under the section on Improvised Weapons, this rule shows up:

If a character uses a ranged weapon to make a melee attack, or throws a melee weapon that does not have the thrown property, it also deals 1d4 damage.

Does this allow for melee attacks with ranged weapons, rather than simply treating the ranged weapon as an object for the purposes of this line:

An improvised weapon includes any object you can wield in one or two hands.

If I attack with a ranged weapon that has the Ammunition property, can I use it as a ranged weapon (and keep its properties) or must it be an improvised weapon?

Can I make a melee attack with a ranged weapon?

Are there any rules that preclude this action?

I know weapons with the Ammunition property are treated as improvised weapons per this line and this question:

If you use a weapon that has the ammunition property to make a melee attack, you treat the weapon as an improvised weapon .

… but what about darts and nets? Am I forced to use them as an improvised weapon to make this melee attack or can I simply make an attack with the ranged weapon (including any properties therein)?

Keep in mind, I am almost certain this isn’t the intended result, but what is RAW?

What does the Poison Weapon rogue feat do?

Here is the feat:

Poison Weapon ->
Requirements: You are wielding a piercing or slashing weapon and have a free hand

You apply a poison to the required weapon. If your next attack with that weapon before the end of your next turn hits and deals damage, it applies the effects of the poison, provided that poison can be delivered by contact or injury. If you critically fail the attack roll, the poison is wasted as normal.

(It also allows you to create simple poisons, which are not part of my question.)

The rules for injury poisons are as follows:

Injury: An injury poison is activated by applying it to a weapon, and it affects the target of the first Strike made using the poisoned weapon. If that Strike is a success and deals piercing or slashing damage, the target must attempt a saving throw against the poison. On a failed Strike, the target is unaffected, but the poison remains on the weapon and you can try again. On a critical failure, or if the Strike fails to deal slashing or piercing damage for some other reason, the poison is spent but the target is unaffected.

Without the feat, using poison seems pretty straightforward: you spend the listed number of actions to apply a poison, and it lasts seemingly indefinitely until you make a Strike and deal piercing or slashing damage (or critically fail a Strike).

But the rogue feat confuses me. Specifically, what happens if you fail to Strike someone by the end of your next turn? Is the poison wasted? Wouldn’t that make someone who uses this feat worse at delivering poisons than someone who doesn’t?

Vampiric touch and 2- weapon fighting [on hold]

Once I have cast Vampiric touch I can make a melee spell attack. In the first round, the round I cast the spell my action is to ‘cast a spell’ and a I clearly can not use two-weapon fighting. However, in subsequent rounds my action is to make an attack. Does this attack allow me to use the two-weapon fighting rule and make an attack with a light weapon in my off hand as a bonus action?

Two-weapon fighting stipulates that you must make an attack with a weapon. So the crux of the question: is a melee spell attack with Vampiric touch equivalent to attacking with a weapon? I would consider a hand that can do 3d6 necrotic damage a weapon.

Drawing a weapon during a Charge attack

Charge is a full-round action; can you also draw your weapon as part of that Charge using the rule that characters with at least +1 BAB can draw their weapon as part of a move action? Although a Charge does involve movement, it is not a move action. So, assuming a character does not have Quick Draw, but does have a BAB in excess of +1, is it possible to Charge and unsheath/attack with a sheathed weapon in a single turn? I cannot find anything in the rulebooks, and this seems like a glaring omission.

Is it possible to hit multiple enemies with a two-handed weapon?

My players want to hit multiple enemies with two handed weapons, like cleave, but I can’t find anything in the rules. The most I’ve given them so far is on a critical roll; They can hit the enemies if they are close enough to each other i.e. shoulder to shoulder. This seems fair on smaller targets like kobolds. I figured maybe Unearthed Arcana guidance might be out there, but couldn’t find any. I’m guessing this was to simplify rules or maybe they will expand it officially later… Any ideas?

Does two weapon fighting’s qualifying “attack” have to be part of the “Attack” action?

The rules for two-weapon fighting state:

When you take the Attack action and attack with a light melee weapon that you’re holding in one hand, you can use a bonus action to attack with a different light melee weapon that you’re holding in the other hand.

Emphasis mine. Now, under most circumstances you would wield two light melee weapons, attack with at least one of them during your Attack action, and attack again as a bonus action. However, the rules themselves just say “take the Attack action and attack with a light melee weapon”, not specifically “take the Attack action to attack with a light melee weapon” or “attack with a light melee weapon during an Attack action”.

In other words, both the requirements “took the Attack action” and “made an attack with a light melee weapon held in one hand” need to be met during a turn, but the light melee weapon could be used to attack separately from the Attack action. Is that correct?

An example for how to accomplish this: An Eldritch Knight Fighter takes the booming blade cantrip and the Dual Wielder feat. That Fighter takes the Attack action, attacking with a Greatsword, then uses Action Surge to take an additional action. He drops the Greatsword (everything I’ve seen indicates that dropping a weapon doesn’t even require an object interaction), then draws two light melee weapons as permitted by Dual Wielder. For the second action, the Fighter casts booming blade (SCAG, p. 142) which states:

As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell’s range

Thus, after those two actions the Fighter would have both taken the Attack action and made an attack with a light melee weapon in the same turn, and I would expect he could use two-weapon fighting to make a bonus action attack with the weapon not used during booming blade.

Note that this scenario is just an example; I’m not 100% certain there’s a way to cast booming blade while holding two melee weapons, but I know there are other ways to make an attack outside of the Attack action and I just couldn’t find one quickly that was more definitively possible.

Great Weapon Master vs. Dual Wielder for a Barbarian

I’m going to play a half-orc Barbarian (with a STR modifier of +4) in a soon-to-begin D&D 5E campaign, starting at level 1, and I’m wondering what the best overall attacking style is, combined with the corresponding feat: one great weapon (d12) or two regular weapons (2d8)?

I’ve almost always seen barbarians played with Great Weapon Master and a two-handed weapon (usually a greataxe), exploiting the advantage on attack rolls granted by Reckless Attack as a mean to both counteract the -5 to the hit and increase the likelihood of a natural 20, by which the feat also grants another attack. Altogether, at level 1, I could deal a maximum of 28 damage (12 + 4 STR + 2 rage + 10 GWM), increasing to an utterly disgusting – also thanks to the half-orc’s Savage Attacks – 104 damage (2x 3×12 + 2x 4 + 2x 2 + 2x 10 GWM) when critting both the regular and the bonus action attack granted by Great Weapon Master. However, that comes at the cost of a reduced probability of hitting or, when using Reckless Attack after level 2, a higher chance of being hit.

The Dual Wielder feat caught my attention both for the free +1 AC when weilding two weapons and the ability to use two non-light weapons at the same time, e.g., battleaxes. In case you don’t remember, when weilding two weapons, one can use a bonus action to attack a second time, without adding the ability modifier to the damage. The output is lower, at maximum 24 (2x 8 + 4 + 2x 2), or 56 when critting with both attacks (6x 8 + 4 + 2x 2), but the chance of hitting is higher and that of being hit is lower thanks to the bonus AC, even with Reckless Attack. Also, when Extra Attack becomes available, one can regularly attack three times in the same turn (2 with the action and 1 with the bonus action), increasing (?) both the average damage done without critting and the chance of critting even more (as far as I understand, the more attack rolls you do, the more you might crit in a turn), possibly allowing not to rely on Reckless Attack to consistently deal damage.

Overall, while Great Weapon Master opens the possibility of dealing an insane amount of damage even at low levels, Dual Wielder appears to be more reliable for both attack and defense. I’m afraid to be missing something though, as I’m an ignorant in statistics and my understanding of probability is quite poor. May I ask for your opinions? Is the potential damage output with Great Weapon Master too good to be traded off for less damage, but a bit more reliability and defense?

I was also thinking of multiclassing 3 levels of Fighter to add the complementing class feature (Great/Two Weapon Fighting) and exploit Action Surge and the Champion archetype critical bonus, but that might as well be another question.