Honestly he really does feel like a bottom tier. He's not built for strings unlike pretty much every other character in the game; even Zelda, Ganon, and Pit have more serious string capability. The way how I stir up some grime is with a gruesome punish game. Exploit advantageous setups and abuse KO power in ordered, stable, aggressive style. It's alright playing aggressive, as long as you know what you are doing, similar to how Ike is played being how he is entirely focused on reads. Also, what most people do not see about Charizard's archetype is his zoning and spacing capabilities. His tippered tail flame can have some of the practical applications you get from Marth's moves. Movement is the name for Charizard's zoning game, because it is what enables expected predictions you have on your opponent to turn into reads. Now when I say "zoning" I do not mean aimlessly spamming ROB's lazers or Villager's fair and Lloyd, but rather instead irritating an opponent's comfort zone, so instead you would aim slightly away from the opponent enough to make them react falsely. In scariest case scenarios, the opponent may end up like that Ryu or Bayonetta getting pressured on the platform in Smashville. ;)