A more subtle issue is focus. If you try to build a mystic adept who can do everything, will he end up mediocre all around and not actually that impressive? I decided to give it a shot -- there's definitely a lot of careful balancing required, but it wasn't crippling. I think a summoning-focused magician is still a more powerful and flexible build, but this guy turned out to be pretty impressive.
There are, of course, many ways you can build a mystic adept. Since adept powers don't support spellcasting or summoning very well, I went with a combat adept who uses spells and summoning for buffing and utility:
Edit: the Missions "hot patch" errata increases the cost per power point to 5 karma, and that's expected to become official errata. The character below was modified to account for that.
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On offense, Fade has great initiative and ~20 dice with automatics (varies a bit depending on whether Attribute Boost is in effect). For most targets, he can either split his dice pool with multiple attacks or make a called shot (Vitals) to boost DV without bumping into the accuracy limit. He's also good at unarmed combat with shock gloves, but that's definitely secondary. Finally, he has Control Thoughts as a completely different attack angle.
On defense, he's good but not great -- until you add in the sustained spells. Fade can keep Armor, Combat Sense, and Improved Invisibility sustained on himself via foci and Focused Concentration. They'd all be at Force 1, with more hits allowed via either reagents or Edge. That can give him 18 dice on defense (with potentially 11 more dice via dodging and full defense), armor of 20, and opponents suffering blind fire modifiers. His body is only 3, but between the defense dice, armor, and magical healing, that shouldn't be a big concern. Fade also has a spell defense pool of 5.
Outside of combat, Fade has solid perception and sneaking (mostly from attributes rather than skills), can summon weak spirits for their powers or general utility, and has a large and flexible array of spells. He's actually quite a strong caster, but his drain resistance is only moderate. That's tough if you're trying for big combat spells, but most utility spells work just fine with minimal drain and possibly a few reagents.