Can a hybrid character replace his only encounter attack power belonging to one of his classes?

Assume a Paladin|Swordmage with Cha and Con dumping Int or a SwarmDriud|Runepriest with Wis and Con dumping Str. As the relevant ability is very low, it would make sense not to pick any power from the secondary class. However, hybrid rules say you must.
Is there a way around this?

I do not think Reserve Maneuver or multiclass power swaps work, but I am not sure.