Fromper: I'll guess that he wants to add force spells from other classes to his spell list. And maybe to later use 2 PP to get 30 Magic Missile spells on a scroll which he can use at his caster level.
I don't think the 1 level bump in spell level is worth it, and he'd be losing a spellcasting level too.
(The endless blasts from scrolls though...quite tempting, even if tactically dull.)
Here's an alternative route:
Shaman w/ Lore Spirit & Arcane Enlightenment Hex
You'd choose the hex at 2nd anyway, so if you're still 1st, it's a decent switch. Aasimar is also the best fit because all 3 mental stats bolster the (very key) hex.
As well as all the flavorful archetypes/hexes/wandering spirits, there's the Spiritual Guardian feat if you're into Spiritual Weapon (et al). (Not a recommendation. Magic Missile is too superior, as is Admonishing Ray as mentioned above.)
Just my 2 c.p.