Anyway, I guess my main barrier with the character Isaac is how incredibly straight forward he is in many ways, which is a bit of a discouragement because it kind of signifies that what could come out of the character will not be utilized to the fullest. As far as I can tell, he's going to have standard sword play as his standard attacks and have those psynergy capabilities as his specials. That's not really interesting, if he wasn't portrayed as so generic I could see more put into him, but right now it's basically standard stuff. I blame actually playing Golden Sun.
What's wrong with that? Since when has being generic personality-wise mattered? We have Link, we have Pokemon Trainer, we have tons of silent protagonists. Doesn't mean his moveset would be bland. We don't really have a magic/swordplay user yet, and even if we did your argument just sounds like the anti-sword-wielder one. But those arguments, while not entirely logical, as sword users can play completely differently from each other, at least raise the point of the same overall weapon. You're saying he'd have something completely new to Smash, (likely earth-related) psynergy, as well as sword attacks, and yet, that's not interesting?
Sounds pretty subjective to me. Sounds like you just don't care for Isaac, which is fine, but therefore think he wouldn't be an interesting character? He literally offers something not only different from any other character on the roster, but from any other potential candidate not from GS, as well as one of the potentially flashiest movesets, what about that isn't interesting? It's not like he would have a moveset as limited as Sonic or DK, or one revolving around a single weapon, like Marth or something.
Really, the same could be said for any character. I find Takamaru not really interesting, he's portrayed as quite generic, and as far as I can tell he's going to have standard sword play as his standard attacks and those ninja capabilities as his specials. I blame actually playing Nazo no Murasamejo.