Hi, I'd like to post my thoughts on this subject: more specifically, the trickiness I've seen in balancing Magic or Supernatural Powers with Technology or Psionics in one system. Here's the rundown as far as I've seen, in both tabletop RPGs and video games. Either the game is purely centered in one genre and thus has only one half of the equation, or it's a hybrid but favors one half heavily. Examples of the first category are easy: Fantasy games such as Dungeons & Dragons, or video games like Dragon Age, are purely medieval fantasy, and thus have massive magics/powers available, no psionics and no technology beyond blacksmithing. Scifi games like Mass Effect or Bioshock arguably have purely psionics and high tech gadgets, with no magical wizardry or "racial powers" to speak of. Now, to illustrate the second category, take RIFTS the RPG for example. Supposedly, a setting of future earth with an even power balance between Magic/Supernatural Creatures and Psionics/Tech, all vying for control of earth. Except, beyond the innate lack of power balance in the system everywhere, Magic is gimped and underdeveloped, and only godlike supernatural creatures like hatchling dragons have a chance against the might tech and psionics can bring to bear. This is a trend I see increasingly nowadays, and in some ways it makes sense. It makes me think that because we are such a technologically advancing society, it becomes easier to just pawn off magic on a "D&D-style spell list", have a few staple fantasy races, and then focus on the much more true-to-life Psionics and Tech, as we have that going on in the real world(at least the tech, anyway). And it frustrates me. I like playing both, but it never seems like any game has a real, useful power balance to have both equal in any given setting where they're combined.
This brings me to a side topic, the difference between magic and psionics. I've delineated it before to friends, but I'd like to state it here as well. To me, most systems fail at distinguishing between magic and psionics as clearly different animals, other than establishing that magic has most of the physical powers and psionics most of the mental. So, a few key things that distinguish magic from psionics:
1) Magic is from without, often draws on the land or other natural powers, and is often a boon from a higher realm/power. Psionics is from within, draws on inner strength or mental willpower, and is often an evolution of human mental capacity.
2)Magic is inherently chaotic, and can have drawbacks or unexpected consequences regularly, can basically do everything but not as skilled at doing a single thing. Psionics is inherently structured, and usually has no drawbacks other than fatigue(unless you're battling another psionic), and is highly limited to specific things but does them amazingly well.
3)Magic warps reality itself to the whims of the caster, changing things like natural laws to create any kind of effect imaginable. (See Mage or Ars Magica for what I consider the only "high magic" systems.) Psionics are clearly delineated effects, useable in specific areas of effect, but very high-powered in those areas.
4)Tech is used with both sides fairly regularly, but seems to be more conducive to psionics than magic, see Shadowrun 4e for examples of this and how it balances play.
5)Supernatural powers are mechanically indistinguishable from psionics, with the difference being different fuels for said powers, and the powers being based on something fantastic, like a fictional race's inherent powers or a freak accident that creates a superhero somehow.