Re: Sword Art Online-esque (VR Simulation) Game
Icedark - All three systems talked about are points-based systems.
I would ask what you mean by 'organic character growth'? If you're talking about if someone uses their, say, firebolt attack more and more, the ability gets more powerful, then a point-based system works well for that. As you gain XP, you can put those points into skills, abilities, feats, etc., and grow them as you please. The benefit of these systems is that they are already pretty well balanced, as long as you keep some GM oversight.
Champions/HERO System is a robust system that can make literally anything you can think of, and if you consider that Endurance (the energy you use for most powers/abilities) regenerates quickly once out of combat (minutes instead of hours like BESM) then it makes it a good substitute for MP like you'd see in many video games. When going for an RPG feel, where you can rest for a bit and be back to full strength, MP-wise, that's a better fit IMO than BESM.
Likewise, it has a more tactical feel to it than BESM, which works with many RPGs.
HERO is originally designed for superhero games, but there are guidelines for fantasy, street-level heroes, sci-fi, and so on. Also, there are a series of maneuvers, including Martial Arts maneuvers, that allow more customization. And a fancy sword gained through looting a monster could easily be statted up in several different ways, especially if the sword had secondary abilities (such as being able to launch a fireball as a spell, or giving the wielder enhanced speed).