Unless I'm mistaken, they nerfed quite a lot of stuff... Usmash and up-B both seem to have much smaller hitboxes (maybe it's just the graphics, but it doesn't seem like it). Up-B was one of my main KO moves and now it frequently knocks opponents away during the rising part making it much less likely to finish with the sweetspot before they escape. This could also possibly be CPUs DIing out of it better than humans? Not sure. Usmash is still good, so that doesn't bother me too much. Water gun is still annoying because of how it just makes the opponent slide unless you're right next to them, in which case what use is a projectile?
I'd suggest changing it into a sort of short, cone-shaped, shotgun-style water blast (like
this Fludd attack in Super Mario Sunshine). Give it decent KB on a small sweetspot next to Squirtle's head, an outer later of reduced KB, and then outside of that a slight pushback with no % (I'd prefer not having that part at all, but everyone seems insistent on having moves that push people around for some reason). Squirtle's KO ability is still his main problem, and nerfing up-B and usmash only made the problem worse. At least now he could have a horizontal KO move (fsmash is so slow it hardly counts) to catch people's juggle DI. If they DI away expecting a uair, you can Water Gun them in the face and send them flying. If they DI up to survive the WG, you can continue your juggle or up-B to KO. A simple and elegant mixup. It'd also give Squirtle a quick ground move with decent KB which he currently lacks. Ftilt is the best move for that kind of scenario atm, but no one's really afraid of missing DI on Squirtle's ftilt.
Dsmash seems to have reduced cooldown, so I'm happy about that. I think it's weaker, but I'll take actually being able to combo out of it any day. Dair is probably my favorite change. Idk if the team actually read my post suggesting a Fox-like drill, but that's basically what we got. The last hitbox popping them up was even better than what I had in mind as it lets you control whether you keep the opponent grounded or not. Not too familiar with how well it combos into utilt or other ground moves if you keep them grounded, but it's at least possible even if only at high percents, and you can always grab after to beat buffered shielding anyway (or pop them up so you don't have to worry about it in the first place).
I LOVE the new crawl attack, but I wish it would just be swapped with ftilt. I guess you'd lose angled ftilts, but the crawl attack is so much more useful that I'd probably use it in most of the scenarios I previously used ftilt in (and plenty in which ftilt would have been useless). I guess I'm really just saying to get rid of ftilt and replace it with the crawl attack (and just have no crawl attack). I hate waiting for Squirtle to go into the crouch before I can do the attack, and if I do it a bit early I ftilt. I guess I should just get better at executing it, but it just feels unintuitive to be doing the same exact input and receiving different attacks based on whether my WD lag or w/e is over long enough before the actual attack. Either way, whoever designed that attack should pat themselves on their back. I think redesigning all of the movement attacks of other characters in a similar way would do some good for P:M (Ike's, Sonic's, and Wario's side-B). A short, quick boost with a definitive ending point is much less flexible which actually encourages better spacing and situational awareness of when those moves will hit or not as opposed to using the move and adjusting your timing to suit almost any situation.
One specific thing I miss is being able to jump while turning around during withdraw. Not sure why that was removed, honestly... Uthrow and DA seem to have less cooldown, but I might just be imagining that. DA also seems stronger, but I never used that attack so I have no idea. lol Overall, pretty happy with the changes. I think turning water gun into a move with some decent KB will round out Squirtle well enough that he will feel well balanced.