Mr. Game & Watch: As Mr. Game & Watch, I feel his early game is similar to many others in that he relies on his down throw. What he can do from there is completely dependent on match-ups (only follow-up on Sheik and Greninja is jab until they're at like 50%...), with some taking massive damage from his up tilt and nair. He can easily get most characters to about 60% very fast, but from there he has huge problems. Ridley-sized problems. Well, almost.
His kills before 180% come from people running into your smash attacks (sweetspot down smash is insanely strong but hard to hit, up smash only really good for people coming down on you with an attack, side smash is a "safer" option compared to down smash but less kill power), or he can kill some characters with fair and down air gimps. The thing is, there are a lot of characters that have everything they need to avoid getting hit by any of G&W's kill moves, such as Sonic (3fast5me), Duck Hunt, Link/Toon Link, and Megaman (maybe. I'm not sure if G&W can bucket the lemons or not, or how strong a lemon oil panic would even be...).
And let's be real, while it would be nice to think the down throw into Judgement makes him amazing, there will be just as many matches where 90% of your hammers are 1's and will basically give free stocks to your opponent. He is effectively a giant gimmick with few reliable strengths.
Changes:
F-Air: Less landing lag, slightly more hitstun. Like Jigglypuff or even Palutena, this is the move he will be throwing out very often to space out his opponents. Unlike Jigglypuff, G&W does not have the air speed to quickly fair in and fall back if shielded or it didn't hit, and yet he has enough landing lag that he can often be punished for trying to do what he's built to do. And unlike Palutena, it does not have enough hitstun to string into a grab or dash attack (again, landing lag) unless your opponent has a slow reaction to it. Like I said before, he can down throw combo a quick 60% but getting your opponent to typical kill % with G&W's random hits can take years because of the lack of reliable follow ups. I wouldn't mind seeing it kill earlier too (it's generally what he uses to kill at 180%) but I'd rather see it chain into some kind of follow up.
B-Air: Again, less landing lag would be very helpful, as it's even laggier than his fair. But, more importantly, his bair is currently a terrible option for gimping because it sends at a VERY vertical angle. I'd really like it if it sent at much more of a horizontal angle so it could actually kill instead of saving the person you're trying to gimp for a kill at 150%.
D-Tilt: This move comes out fast but has huge endlag. I know people are saying "wow, you can block projectiles with the windbox," but I don't really get what they're saying because oh... you have a less laggy option called shielding... and you've already got a the up air for wind. Personally, I would like to see it kill at around 130%, but at least make it less laggy.
Bucket: This thing has ridiculous endlag, so much that you can absorb something from halfway across the stage and still get punished for it. For the love of God, as if anyone that knows G&W would let it get filled, it needs to be faster. Also, as for Oil Panic, if G&W uses it but gets hit while it's still moving, the attack should not just disappear. It's like if Samus' projectiles just disappeared if she got hit while they were flying across the stage.
Judgement: This is something a lot of people will probably disagree with, but I would just love if all of the numbers besides 9 and 6 got buffed. They're useless. And while it seems like a fair trade off all because 9 is usually insta-kill, it's really not. You shouldn't challenge someone with Judgement because if it's a 1, you'll both get hit by whatever it thrown out and take 12% extra damage. I'm not sure if down throw to judgement is ever a true combo, I know it depends on characters, but so many characters can just avoid getting grabbed and G&W's approaches are awful. And if it is a true combo at 0%, it's not insta-kill on anyone but light characters or at the edge of the stage.
1: Should either not damage G&W (especially for TWELVE PERCENT) or should inflict some kind of stun so G&W can't get immediately punished for using it.
3: Should have much better shield pressure. Its shield poke is completely useless. If not shielded, bad reaction time can lead to a free side smash, though.
7: Should straight-up heal him for as much as a 1 does to him.
8: Change freeze to the stun like Pac-Man's Bell. Freeze is useless, and even hitting a frozen opponent with a 9 won't send them anywhere.
The changes I suggested are just adjustments to fit to my complaints about him. To be honest, I think he would be low tier right now and even with those changes he would have just as hard a time against a lot of characters, but it's a start.