In terms of cel-shading ala ArcSys' style for Guilty Gear, I think it's absolutely doable. Even, Snake, the most grounded/realistic character on the roster could be transitioned to a more anime style (or other cel-shaded style) perfectly fine, whereas the vast majority of the remaining roster would actually feel right at home.
As good as I think it'd look though, it's actually not the style I'd be most interested in seeing. The reason for that being ArcSys themselves and cost.
ArcSys does it better than anyone out there, but I think their style fits best on their own games, it's part of what makes them so distinct. If Smash aped their style, even if it was ArcSys themselves being brought in to handle it, I feel it might start stepping into oversaturation, at least for fighting games. (ArcSys alone has GG, DBZF, GBV/R, and DFD under their belt in just the last few years.)
That's not to say I'm entirely opposed mind you, but I would want them to use it a little differently rather than being in Xrd or Strive's style outright. Granblue Versus I think does a fine job of looking distinct enough for example.
That's really more of a minor nitpick though, the real concern is cost. With the way people complain about potential cuts now, I can only imagine a scenario where the art budget siphons from other areas resulting in actual large cuts. I'm one of the people who wouldn't mind starting from scratch again, but the rhetoric this would result in isn't something I want to witness. It'll go from "too many anime swordsmen" to "anime ruined Smash" in general.
