Everybody
Terrarian
I play multiplayer with friends, and we can clearly see a problem with PvP if one person can sit up in the air off-screen indefinitely and drop dynamite/bombs on everyone. It's definitely a problem to have INFINITE double jump. If they had to build a platform up high in order to do that, at least people would have a chance of catching them. Yes it has lower defense but that doesn't mean it is balanced. It's pretty hard to balance infinity.
I only see Harpies at the top of the map (might be a bug due to 14a) so 5 minutes farming them with a water candle and I already have a hundred feathers. Also, if there are other monsters that take up Harpy spawn slots and make the Flight Suit that hard to craft, I'd be concerned that it might excessively increase the value of hardmode Wings and featherfall/gravi potions.
Wings are incredibly powerful as they are, why would you want to have to wear out your spacebar while exploring?
Edit: DivermanSam, go take a nap or something
This guy gets me. As much fun as it was using infinite jumps, it was OP. Also, can I play with you?