The real problem is all the set-to properties basically gutting any methods of progression. I'm pretty sure you can accomplish stupidity with a Small Air Necromental, getting Weapon Finesse and Improved Initiative as further Bonus Feats atop +6 Dexterity and +3 Natural Armor for a total base AC of 18 before any PC tailoring, so you can pretty easily end up untouchable by very nearly everything in the game from your pile of immunities and enormous Reflex save as well as have pretty crazy accuracy... But not really any way of getting more damage.

But then even with 18/18 Str/Dex investment you don't really have many places to go because of those set-to mental scores. You're a dumb beater, and cannot become much of anything more, meaning you're basically competing with Fighter alone because you don't have the scores to fuel anything else.