Hi I'm new to the boards here and am a Charizard main in P:M. I've watched a lot of gameplay from the video thread and noticed that a lot of Zards will connect the last hitbox of a reverse Nair and then fast fall to L-cancel. I've found (although the timing is very strict) that Zard can autocancel his Nair from a shorthop without fast-falling, which trades the 15 frames of landlag from a SHFFL'd Nair for the regular 4-5 frames of standard landlag, which can give Zard a window to dash out of harm's way if the opponent shielded, or dash in if the hit connected. I'm not entirely sure about the frame data here, but it seems quicker than a late SHFFL, and perhaps more useful than a true SHFFL because it can utilize all of Nair's great hitboxes.
One move that I feel might have untapped potential is Flamethrower, although I could be very wrong lol. I'm not sure if it's at all safe, but Flamethrower can eat up shields pretty fast and poke as the shield dwindles. It also works pretty well against crouch cancel, racking up a quick 20% or so while stuffing any counterattack attempts. What uses have you all found for Flamethrower other than the obvious edgeguard potential?
One last question: If you've hit an opponent offstage at an early %, what is you go to move to gimp with?
I actually didn't know that about Nair, but in general, aiming for the backswing is a heck of a lot safer, even if you get a few extra frames from auto cancels. Because in the grand scheme of things it takes maybe 20 frames for an opponent to WD OOS and attack you (not sure if that's right somebody figured it out a while ago). The extra 10 frames you save might not do much in the ultimate scheme of things though it is worth exploring.
Flamethrower is pretty dang useful, edge guards and I've found even ledge hopped it's not half bad because most people try and smash DI through it and eat lil 30-40% and usually end up DI-ing away. Be warned, only use it when you're opponent is pretty dang far from the ledge if you ledge hop it, since it does take a while to come out.
Gimping moves follow in order of usefulness:
The backswing of Nair: it's sort of a semi spike, and it hits really far below the ledge which nullifies perfect spots.
Dtilt: if you hit with the flame portion at the end, it's sort of like Marth's Fsmash in that it hits a tiny bit below the ledge, but it is pretty much a guaranteed KO on most characters if they burn their jumps.
Side-b: also hit below the ledge a little, and has some pretty long duration as well, though if you miss you'll be eating a lot of percent. Otherwise is can either setup for another hit or just straight knock them back
Flamethrower: kind of per character, but still pretty dang useful, just be sure they can't hit you out of it while recovering (i.e. Marth's dolphin slash might hit you with the tip as he rises).
Hope that helped!