The thunderwave spells has the description:
A wave of thunderous force sweeps out from you. Each creature in a 15-foot cube originating from you must make a Constitution saving throw. On a failed save, a creature takes 2d8 thunder damage and is pushed 10 feet away from you. On a successful save, the creature takes half as much damage and isn’t pushed.
When I first read this, a long time ago, I thought it meant that the caster was the centre of the 15 foot cube. Therefore effecting all creatures that surround you. I also assumed that this would not harm the caster in any way. For clarity, I play that it is always centred on the caster, not that they have a choice about its area of effect.
I have since learned from this question and others on the site that this interpretation is incorrect. Indeed nitsua60’s answer to that question explicitly calls out my misconception directly. This other question also rules out a potential RAW compliant work-around.
As I prefer my incorrect version of the spell I have always just allowed it at my table without really worrying about the balance of it. I haven’t found it to be overpowered, however I never used it the RAW way so I’m not sure if there is a difference.
My question is; does allowing thunderwave to be centred-on but not effecting the caster increase its power level?