@@Envy,
Mmm, I can see what you mean. However, if his special moveset was majorly psynergy or more, they'd need to put some kind of limit on how much he can use, like Robin but perhaps a bit different. Because god knows if he could spam all of his psynergy without some kind of limit or punishment he would become the next Meta Knight. Perhaps recoil from certain moves like Charizard's Flare Blitz? I can see his Briar being his down-b move, with the spikes acting as a shield to swords, kicks, etc, basically (Dark) Pit's Guardian Orbitars however it doesn't block projectiles and can only stay up for so long. Ragnarok could work with recoil. His up-b could be a form of Carry where he lifts himself up the stage (?). Neutral B could possibly be Rockslide, as in attacking with rock projectiles that are slow-moving but do good damage and stun on hit (I know it doesn't stun in the game, but Sakurai can make design decisions for the greater good... sometimes for the worse (Bowser not talking, Peach's weird voice), sometimes for the better (Robin's Nosferatu, Zero Suit Samus's entire battle style, Duck Hunt in general)). I haven't played Golden Sun in years, so i'm a bit rusty on my psynergy knowledge.
When i'm bored I do like to make movesets for characters, so perhaps I could brainstorm a creative and more in deph one for Isaac sometime.
Edit: Spelling error