Without wishing to be too down on Max's idea, as its a cool one and it is workable enough, there are a few glitches.
A power 5 focus is illegal at chargen, and incredibly difficult to get hold of afterwards. Power 4 (still respectable) is available if you're allowing Restricted Gear, Power 2 otherwise (personally, 9 dice, even on two spells, is not overly respectable in my book - i don't know how overcasting works with split spells mind).
If you are going with a Power 4 focus, thats 25 buildpoints, that's a pretty impressive amount to be sinking into an option you don't use all the time. Throw in the Mentor Spirit and everything...
Doing the sums in my head, I can see a character doing what he says - and don't get me wrong, I like the general idea - but its not going to do an awful lot else. And you will certainly curse not having enough attribute points. You have specialised in having a lot of ways to kill people without being outstanding at any of them (except maybe melee combat).
I suspect the numbers would show that a augmented Mage, or even a bog-normal Mage using buff spells, would work better. Or the Mystic Adept who mainly uses buff spells. Which isn't exactly news, and doesn't mean Max's Mystic Adept version doesn't work.