Is FD really the worst stage for a falco against Marth because of the 0-death chain grab?
I mean, I get that part but wouldnt a smaller stage (like FoD for example) be worse? He could edgeguard you at a smaller % because the stage is so damn small.
Meanwhile you could mix up your DIs for the chain grab and maybe screw him up? I don't know, thinking aloud here.
People overrate how much the CG matters, but there's a lot of other aspects of FD that are bad for Falco. First of all, you don't have any platforms to combo with. This can be okay if you get a solid pillar going and read their SDI on your shines, but off of stray hits at mid percents, you lose the ability to chase his landing onto plats and potentially kill hiim off the top sooner than you could off the side.
Another major factor that no plats plays is that you basically can't recover at all. Usually only way you're getting back is if they mess up since you don't have the option to ledge cancel side-Bs on even up-B/side-B onto the top plat if you're recovering from high up. You either up-B which Marth can intercept, side-B to the ledge which Marth can cover really well with dtilt, or you side-B on stage and suffer massive lag and have to survival DI a tipper or just get thrown off stage/into an fsmash or combo that sends you off stage. In short, going off stage on FD is not good news, and it's already pretty bad news on other stages.
Furthermore, platforms can be really helpful for neutral or situations where Marth is trying to pin you down, even including during his respawn invincibility. In true neutral situations, a lack of platforms just limits your mixups. There are plenty of situations where you can go onto plats to cover options more efficiently (when Marth is on the ledge is a big one), so playing entirely ground-based will naturally force you into more difficult coverage options. If Marth worked you to the ledge on most stages, you can jump to platforms to regain your composure and find a way back down with lasers or w/e. On FD, you get no such option. If you get trapped to the ledge, there is no "jump over Marth" option, which means the only way to regain stage control is to go through him. As you can imagine, what follows you getting cornered is what usually happens when people without swords try to go through people with swords. To get a brief idea of how this all comes into play, just analyze how useful your FHs are on DL/BF and compare that to FD/PS. FHing is obviously still good, but it's much more based on what your opponent is doing and how you can come down from that FH safely instead of forcing the opponent to react to your upward movement and countering their reaction.
With all this in mind, I don't think FD is some unwinnable stage for Falco vs. Marth. In fact, even though it's quite difficult, I'm tempted to consider DL worse for Marth than FD is for Falco. Marth loses a LOT of stuff on DL that he relies on in the matchup: keeping Falco pinned, limiting recovery options, and compact/nonexistent plats for optimal comboing just to name a few. Just accept the limitations FD imposes on you, and you will be much more prepared to take on Marth or any CGing character on FD. The reason most people get wrecked so hard on FD is because they try to play it like every other stage. Melee's a whole different game without platforms, so make sure you treat it as such.
