Yep. I think your proposal is balanced well. Removing the condition about not using your reaction is both for simplicity
and because no other features in the game (that I can think of anyway) have similar restrictions. It is enough you are limited to one reaction per round.
My concern (and like I said I've never used the feat AS IS or seen anyone take it... so this could be completely unfounded) is that the Riposte won't see much use since most games only go to +4 prof bonus (9-12 levels). Up to 20% of the "first" hits you take become misses, and you get an extra attack when that happens.
If the feat offered a DEX +1 instead, the
could get a PC to the next modifier, and give them a lot more benefits overall IMO. This would also make it simpler. Good thing or bad? Either way. I like the features to be as simple as possible. Nothing about your idea is overly complex of course.
I think there are many ways to make this a better feat and more appealing:
- DEX +1.
- Have the parry AC bonus extend for any additional attacks made by that target. (Similar to Multiattack Defense of Ranger Hunters.)
- Targets have disadvantage on attempts to disarm you.
- Riposte for a "counter-attack".
- Disadvantage on further attacks by that creature.
- Advantage on your next attack before the end of your next turn.
I'm sure there are others I forgot. Any combination or single additional feature could be enough, just depends on how much better you want to make the feat.