To argue for the 2% healing advantage, I'll say this. It can be a game changer in a lot of close situations. If you are barely in kill percentages, healing is nice. As Rosa, you really can't let him heal all the way for 3 minutes. This is unlike most MUs, where she can just sit there and gravity pull you for 6 minutes if she is up by 1%. I think that is all Pac Mains are really getting at, it forces approaches. That alone is powerful, but if you lose the first stock to ragealina at 40% it doesn't matter.
This. Pac-Man shouldn't be getting Uair cheesed much though.
What is the logic on beating fox? It just seems like a MU that he has a lot of advantages in, but I don't know Pac Man (theory) that well. Fox is suppressive, has a reflector AND a projectile, and kills well, especially with Rage. He is also mobile and packs a huge punch. Seems like a nightmare. Perhaps Pac has some really good gimps on him, and the hydrant helps that? Because lasers can force you to abandon your camping game if done correctly.
I would like to hear why Sinji thinks Pac-Man beats Fox. Pac-Man has the orange on him offstage and some decent OoS options against his pressure, but Fox is a monster in general. I'd put in Fox favor based on my experiences (D1, MegaFox, ThisGuy), but maybe my trouble comes from my style of play. Still, I'd have to see this one to believe it.
So.. fox just shoots the hydrant, then you are exposed to lasers and the hydrant comes at you and fox gets to refresh all his moves when you put a hydrant down. And, germane to the current discussion, how does he deal with fox's safe and deadly pressure with such a crappy grab? Trampoline OOS is alright but the risk/reward really doesn't favor you if you are relying on it.
Lasers aren't that big of a deal. They never launch the hydrant, nor do they count towards lowering its HP, so it's in Fox's best interest to keep chasing Pac-Man down. Hitting Hydrant also doesn't unstale/stale moves. Test some stuff out first! Trampoline is, as you said, a decent response to his pressure. Fox doesn't have the most range and trampoline doesn't really care about his cross ups, so for a character that doesn't get THAT much off of grabs, it's nice to have against him.
I'm not even going to waste my time with that tier list. A character who struggles to kill (and struggles even harder when you have matchup experience) has a 7-3 favorable matchup with Link.
Nevermind that Link can abuse rage quite well in this matchup, block fruit just by standing still, destroy and send Fire Hydrant right back at him with one sweetspot up air, one forward tilt(?), and two down tilts.
I've have to see some high level gameplay of Pac-Man stomping Link before I gave it a 7-3. If haven't fought any big name Link players myself, so I can't say much on the matter.
I know Pac-Man players love to tout Power Pellet healing as the answer to Rosalina, but honestly? Compared to getting pummeled with fruit and hydrants, not to mention the crazy traps and setups Pac-Man can do with said fruit and hydrant, the ability to give all that a giant middle finger at the cost of 2% healing for Pac-Man is a trade I will take every time. That's literally a single jab, hardly a gamechanger.
At the end of the day, it forces the approach. That's a win in my book, and something very few characters can claim vs Rosa.
Random thought: Would GP be of any use for dealing with z-drop shenanigans?
Probably, but it's probably not safe either since Pac-Man is most likely right above your head.
I'd say the best time to use the hydrant is when you're above Rosalina. She can't oneshot it with uair, and the hitboxes won't cancel it because Luma is Luma and Rosalina's ring is transcendent. So her options are to GP (punishable if you're close enough, and I mean actual damage not Power Pellet healing), airdodge (which means it still hits Luma), or GTFO (yay, you have some stage control).
The best time is whenever Pac-Man wants to, unless Rosa is right there to punish. I rarely try to punish Rosa when a hydrant is swirling around her because it can still hit Pac-Man, whereas the heal is safe. Those 2% heals add up fast if you keep spamming GP, so while you aren't taking damage directly, you are hurting yourself indirectly.
I won't pretend to have any high level Pac-Man experience, but given what I know about their tools and my own likely reactions, I'd call it slight advantage to Rosalina at best, but I can accept even as well.
I think it's slightly her favor because her hitboxes are massive and she still has the KO power advantage. Both can edgeguard each other pretty hard and I think Pac-Man wins the patient game, but Rosalina's buttons are dumb.
I mostly think like you. But i'll Put a slight Adventage for Rosaluma, Pac-man will still have a rought time to get pass Luma who will absorb his projectile or Rosalina who can attract them.
Contrary to popular belief, Pac-Man doesn't have much incentive to go over towards her with Luma alive unless he's down a stock or time is running out. From Galaxian upwards, his fruits will pierce through Luma and still hit Rosa, although they can still be cancelled by its attacks. Tumbling fire hydrant will also plow right through it. If Rosa keeps GP'ing whatever he throws, Pac-Man heals. Yes, 2% is small, but it can be the difference between life and death, and the deciding factor in a timeout situation.