Count your blessings, at least Leon HAS good costumes. 
Free Step Dodge
Zeo
Mavis
Lol yeah the ones he does have are good, i would love a couple more though just for some variety.
Rawbietussin
While I love that most of his costumes were from old games, I wish he had something original now, probably a casual DLC.
Mavis
Yeah something similar to Bayman's polo shirt would be really good imo