From what I've seen in this thread the following changes were claimed to have been made (I would imagine based on feeling and placebo):
- Less landing lag on dair
- Better hitboxes on fsmash (though it's been said all multi hitting moves are better)
- Higher jumps
- Faster mechakoopas
- Faster dash speed
- Stronger uthrow
- Slower bair
- Something about his nair being changed? I don't remember what exactly
- Bair not auto cancelling anymore out of a full hop
- Something about the reticules in his smashes
- Bair being autocancellable when it wasn't before (no idea since I don't use Duck Hunt)
- Nerfed jab lock though not to the extent Link was
- Lower dash speed
- Usmash connecting better
- Fair having a sweetspot and sourspot
- I think something was mentioned about dsmash, don't recall what
- Shadow Sneak stuff being removed
- Faster ftilt/dtilt/nair/some other aerial
- Stronger or weaker dair
- Weaker rest
- More speed (dash or air, don't recall)
- Sing being more difficult to wake up from
- KO punch always going forward
- Stronger knockback on smashes
- Higher jumps/wall jump
- More distance on side special and up special
- Bthrow killing earlier (pretty sure the person I saw mention this, later deconfirmed it themselves)
- Cape glide coming back
- Not specific to Megaman but the inability to ftilt/fsmash with an item affects him
- Leaf Shield projectile being faster
- Uair being stronger knockback-wise
- Bthrow being weaker
- Bat making sound when reflecting stuff
- PK Fire being easier to escape
- Something to do with PK Thunder. More damage? Don't recall
- Turnips being bouncier
- Dsmash doing less damage
Don't recall any claims being made for Pika, just a lot of people asking about changes
- Faster Guardian Orbitars (start up wise)
- More horizontal range on usmash
- Less lag on arrows
- All kinds of stuff, mostly damage and knockback buffs on things like aerials and smashes and tilts. Back Slash doing more damage to the front, uair being less laggy (I know you can full hop uair and then double jump, not sure if that was a thing before)
- Some glitch with Yoshi being removed
- Bair nerfed
- Fsmash buffed
- Can't Pocket Pac-Man's trampoline anymore (technically a Pac-Man change)
- Up special being slower
- Pretty sure there were claims regarding grab or throws, less lag or something
Don't recall any claims for Wario
- Uair nerfed damage (iirc Thinkamen himself said that was placebo and that it either got nerfed in an earlier patch or always did that damage)
- Less lag on grab
- Damage changes to ftilt and/or dash attack
That's all I recall and I'm not claiming any of these to be true changes due to the patch. I'm just listing the claimed changes I recall being listed earlier. If any of these are true then they should be listed in the op, if not then these characters can all be ignored I suppose. I'd test it myself but I already updated both my 3DS and Wii U version.
If none of these are true then maybe this post can stand as a list of what HASN'T been changed in case someone suggests one of these again.
I'm aware I'm ignoring claims like Ganon's utilt having more range but I just feel it's best to get the characters without any changes out of the way and this post is long (and probably pointless) enough