Excuse the TRIPLE POST right now but guys: holding a grenade while landing cancels all landing lag. How did I never notice this before?
You might be thinking a bit too hard about this. Having a grenade pulled out in the shield-able frames does let you shield on frame 1, but if you're planning on shield pulling a grenade in the first place, you might as well stand and pull a grenade, since the shield times are the same regardless of whether you start it on the ground or in the air. The only times you'd be able to take advantage of that is when you're in the air, but Snake's largely a ground-based character, so you're probably not going to stay 19 frames above ground (Pulling out a grenade early requires 21 on certain frames, actually), unless:
1. You're coming back from a combo- It might have some merit here, since a cooked grenade is oftentimes more valuable than a fresh one if you plan to act immediately. Personally, I pull out a defensive grenade after a C4 stick if they're not in definite back air range or if I'm too lazy to think, because of the extra cooking time, no-landing-lag thing, and the fact that they're probably at a percent where a grenade will send them up a somewhat decent distance, which is oftentimes disadvantageous.
2. You're dropping through a platform- I personally prefer to roll a grenade in most of these case instead of dropping through, but this might have some merit too
3. You're coming back from getting comboed- If you don't have a grenade pulled out by the time you're in range of the opponent, you're likely down airing an overextended opponent, backairing a really badly spaced opponent, or doing something wrong.
(Basically, there aren't many opportunities Snake can use the lack of landing lag from a pulled grenade)
EDIT: As for Messi's Snake...You know how I think about most Snakes that aren't mine (and even Snakes that are mine). Admittedly, he's using standard grenade tactics better, but there are a lot of things he's doing that confuse me in the not-good way that can't be chalked up to misinputs, and his combo game seems to be off: I've noticed that he's been abusing down airs in not-optimal ways (I.E. a down air clearly wouldn't hit cleanly from that distance, yet he does it anyways), and he's been using cypher->back air a lot without thinking. He does react much faster than I do, though, which explains both why he got and lost many opportunities to do cool things and why some of his choices were suboptimal.
The rest seems to be textbook stuff, which unfortunately I value less for Snake players. It's possible that he found a lot of this himself though since I don't see him lurking the Snake boards (and because what I consider textbook might not necessarily be textbook anyways), which could explain things.
He does have a much better ability to adapt/change muscle memory than I have and a faster reaction time, which is good.
As for the other players, they seem to be adapting to Snake somewhat better (a lot better since the Rolex+Prof glory days of dominance), but there's a semi-obvious lack of anti-Snake research for other players. (Axe did make the good observation that Snake can be stage spiked after a stage-tech, though that could be averted with a walljump-tech B-reverse-cypher)
M2K seemed to be lost in general though (Slow reactions, bad techrolls, etc). I don't know why; he's been fairly bad at dealing with mines and whatnot, though it seemed especially bad in this set. Maybe he's getting old...? (The "This is Snake's worst matchup" vs M2K's Falcon was pretty funny though)
Upon further analysis, though, it's possible that his poop-bombs-from-the-ceiling gameplay works well on M2K, simply because he's not good at dealing with them; I know it worked for me during the weekly right before I got home from college.
EDIT2: Never mind, seems like he figured out a lot of this stuff out himself. Saw him going for the backwards crawl to the ledge, which was one of the things I was hoping to experiment more with before I said anything about. It's likely safe to assume he found a lot of the stuff himself, so good for him.
tl;dr thoughts: Messi's not as bad as I figured he was going to be originally, though he needs to slow down a bit and think. As things are right now, they're working out well for him because Messi's gets in his opponent's face quickly, but I'd imagine that most Snake players with a reasonable amount of character knowledge can see lots of holes in his gameplay