Apparently, judging from the responses (and my own experiences with another player's Sorcerer Pixie) -
Q: How do you kill a Pixie Sorcerer 8?
A: Very easily.
Not only do high LA creatures like the pixie make poor arcanists but the loss of 4 levels worth of HPs in this case (yes, even if they are only d4+Con) makes for an arcanist that very easily goes *squish*.
Not to mention the effects high winds and grapples have on such a character. Most of the time such a character will hide and runaway from nasty encounters, often leaving a disgruntled party behind that have take some serious losses when trying to fight the encounter 1 character....um, short.