There's stuff they could do to Ganondorf to make him still feel like his old self, while losing most/all of Falcon's roots.
Add a charge to Warlock Punch. So if you tap it, it's classic Warlock Punch, but hold the button down and Ganondorf charges an energy attack. You wouldn't be able to hold the charge or anything like that, it would be more like Mega Man's side smash.
Down Special can be that slam attack. It's thematically similar to Wizard's Foot, and "close enough" in function to not be a total redo. Pit's Down Special is similar, in that it's an entirely new move, but is similar in function to Pit's old Down Special, just with enough changes that it feels like a new move.
His Side Special is already fine.
I have no idea what to do with his Up Special. Besides a hover or whatever, but I'm not a huge fan of that because it feels like too much recovery for Ganondorf. And it take a little away from Peach's gimmick.
And they don't necessarily have to change Ganondorf, either. If they change some of Falcon's moves, Ganondorf then has a unique move. Toon Link and Roy both had this. Link's Dash Attack changed, and Marth's neutral special changed, leaving Toon Link and Roy with unique animations/functions for those, despite not changing. I think Falcon's Down Throw is a good example of this. Falcon's a strong dude, but one handedly chucking an enemy down into a slam fits Ganondorf a lot more, and Falcon is generic enough that they could make up whatever as a replacement Down Throw.
I'm not a fan of making Ganondorf all magic. There's a certain symmetry with the three Triforce holders in Smash. Link is gadgets and a sword, Zelda is magic, and Ganondorf is brutal close combat. That fits their Triforce roles perfectly, and giving Ganondorf a magic based move set loses that balance between the three.
I would only change one mayor element, instead of his Warlock Punch he has a extreme build up power up similar to Cloud.
The biggest weak point of his design is his need to approach is opponent. He is slow, has slow moves and no particle to balance it out (like Robin). He should get a tool, which forces his opponents to come to him. This also would be in the sprit of his character: A villain with a masterplan you need to stop.
So instead of the Warlock Punch he can channel evil power with his Triforce of power. This and hitting his opponent fills a bar (physical hits on him reduces it). If he reaches maximum, what can take very long, he can transform into Ganon. Ganon is an overpowered monster similar to Giga Bowser. He stays in this form for a limited time before transforming back.
You really don't want Ganondorf charging up, so you have to approach him. Since Ganondorf isn't fast, so he can't really abuse this power. But he is more then happy, that you want so spare with his powerful moves.
In my opinion this idea has everything. He is still a Semi Captain Falcon clone, there is a lot of fanservice with Ganon, the fighter concept of his character would finally work, you really feel like Ganondorf, a demonic, overlord, who bears the Triforce of Power, and fighting him, feels like stopping a villain before he destroys everything!
If the NX's rumoured specs are true, then there's no way the Ice Climbers would be causing problems. Not a guarantee for them being back, but it seems like Sakurai likes them a lot, so probable.
The question is, what Smash for NX will be: "Smash for NX" or "Smash for WiiU, 3DS and NX". With the second one they properly would update all three games to play the same., so no Ice Climbers.
But i believe, we will get a Ultra Smash Brothers for NX, which isn't compatible with the other version. First the NX is a paradigm change for Nintendo, keeping such a connection to one of there unsuccessful generations would be strange, second it would limited the future of more DLC, since Smash 4 is a great game to build a service on, and the NX is supposed to have no backwards compatible, so you need a good reason, why we should buy the game again.
I got bodied yesterday by a Bowser. His grab game is sick and requires immaculate spacing and mixing your landing options all the time, which at my level is something that can't be done consistently the 100% of the time.
I'm a Bowser Main and love his play style. Another important element is patience. Yes, you get comboed a lot, but Bowser can take it and with one or two moves balance the score out again.