The problem with this character is that everything he does is very punishable. Even his beefy attacks, his supposed strength as a "mighty glacier", can simply be shielded or dodged safely. Once in his personal space, Ganon has attacks and grabs that are too short or slow and he gets destroyed. Everything he does in the air is easily readable and punishable, so he gets destroyed there too. His recovery options are very poor and with his short air jump and bad horizontal speed, he can get gimped at some very silly percentages for a heavy class character.
The only place Ganon can work well is in the very specific side-b zone, where the enemy can't just auto-shield for the win. For a character who's mobility, attack speed, shield pressure and defensive options are gimped, this is the one spot where he excels and he just doesn't excel that well. In smash, you need to have different options to fake out, mind game and outplay your opponent. Movement and physics are a big part of what makes Smash Bros unique as a fighting game, and when you take that away you just don't have much to work with and you're forced to approach with bad physics and limited, unsafe moves.
Now, Ike is another slow character. But Ike has a gigantic *disjointed* sword arc which gives him range to bait and punish with some amount of on-shield safety. And despite being slow, his jab is quick, his side-b gives him a lot of mobility/recovery and his down-B can punish aggressive characters instantly. He's a slow character, but he still gets some fast moves to deal with the transitions of combat.
Mr. Sakurai seems to think that heavy weight characters need to have that advantage negated through being easy to combo and juggle. He also seems to think those characters automatically need to have massive landing lag on their aerials. For every 1 point of power you gain, you lose 2 points of speed and it just doesn't add up. I mean, Ganon's uTilt is just another version of his neutralB because Sakurai thinks balancing the character around goofing off in free for all is what the game is about and continues to resist the competitive interest in his game.