His Up B doesn't have the float anymore, his ledge grabbox was shrunk, the ledge release glitch was fixed so he doesn't have something like 12 frames of intangibility upon ledge dashing, d tilt tip hitbox --20bkb, dair tip is weaker, DED was cleaned up, everything else was like minor upsmash/down b fixes iirc.
Roy didn't get too many nerfs overall, but they very heavily affect his toolkit. The Up B and Ledge dash/ledge grabbox changes are specifically what're important, as they make all of his risk/reward heavily favored in risk now since he can't cheese up b his way onto the stage. Marth/Roy are probably pretty close now, they're better in specific matchups rather than Roy being strictly better than Marth like he was in 3.5. Claiming that 3.6 Roy is still way better than Marth just shows a lack of experience with either character at high level play.
The lower dash speed and more land lag on aerials compared to marth are pretty relevant, it's not a "small difference". The lowered dash speed means you rely more in your normals, which makes some matchups particularly worse for Roy than Marth (ex. Fox). The additional L cancel landing lag on aerials like Uair and Fair means that they're worse on shield + it's significantly harder to abuse Roys disjoint vs shield since his tips do poor damage. Marth can do stuff like SH late tipper fair on shield and it's incredibly safe due to the additional shield stun and 7f lcancel landing lag, aka Roys SHFFLs aren't just strictly better.
oh no I'm replying to this thread someone please help