Eh, Wario and R.O.B are mid-heavy weight-ish. I'm talking about the REAL heavies. Bowser, D3, Ganon, DK, and Char.
People really oversell charizard's weaknesses. They're a problem, but they're not as bad as people make him out to be. First of all his recovery is
not bad. Nor will I say it's "below average". A below average recovery in my opinion is something like Flacon UpB. or Rosalina's UpB because it's so easy to hit her out of it (yet no one does for some reason).
Charizard's recovery is fine. He'll rarely have trouble making it back to the stage. If he's getting gimped, it's becasue his opponent was good, not because charizard's recovery is bad. He's got an extra jump in the air to reposition himself to make getting the edgeguard more difficult. This means that if he thinks the enemy is going to drop down and challenge the later (unarmored) portions of his upB, he can throw off their timing and (problably) stage spike them with Fly for getting too greedy. He can double jump + Airdodge to get back near the ledge if the enemy is going for an aggressive edgeguard, then he's still got another jump before he's forced to recover. If he's not recovering low, flareblitz is a blazing fireball of death that none dare challenge. He can sweetspot the ledge with this, making his horizontal recovery one of the best.
His hitbox is actually much smaller than your typical super-heavy weight, and he has better tools for escaping juggles than Bowser, DK, or Ganon (I don't know much about D3). He has tools to mix up his landings. Rocksmash will stuff over-aggro juggle attempts.
His followup game is the best of any super heavyweight. He doesn't hit as hard as Ganon or Bowser, but he's got just enough of a combo game to make up for it.
Super heavy weights don't have amazing frame data by nature. We ain't sheik up in here.
He has one of the best kill throws in the game. This is a big deal vs faster characters like shiek, It lets us net the kill off of something as small as a shield grab (Char's shield grab is really good to boot). The top tiers have a habit of putting charizard into rage without really being able to take his stock off. Charizard was really good at abusing rage before. With this he's even scarier.
Yeah, his neutral game isn't the best, but we do at least have flamethrower and Dragon Rush (with customs) to help patch up that weakness. Considering that charizard gets access to so many tools that other super heavies don't get to have (multiple jumps, super armor landing option, mid range projectile that gimps half the cast for no reason) he's going to have to have some tradeoffs somewhere.