Sorry I'm late on this one, but:

1) Electrical Madness: half damage from electricity every time (no soak from resistance; minimum 1 point damage), or else FORT SAVE FOR HALF when they're struck; if they're already only taking half, they make a second to take none or a quarter (minimum 1)
AS SOON AS they're shocked they must make a will saving throw DC10+ damage from electrical attack. If they fail they go berserk (as a barbarian) and attack the nearest living creatures for a number of rounds equal to however much they failed their will save by. Example: 5th level lightening bolt spell dmg does 20 points of damage; save for half; Golem save for 1/4. will save DC15 if they pass both, 20 if only the first, 30 if fail all; save or goes berserk.

sure the PCs could lock them in the room with the evil evoker; but if it's the bbeg, who's been watching them or knows abot the fleshwrought, he could wait until the party is together, zap with a lightening bolt, and let the PCs take out their own.

2) Weak Mind: -2 wis on all builds. Their minds are incredibly fragile. this is on top of any other penalties. additional -2 on all will saves vs mind control.

3) Crappy Healing: There's a chance that any healing spell cast on them will fail. Every time you get one, roll randomly: 1= fails, 2-4= quarter, 5+ regular half healing. Repair skills (seamstress/tailor) works. Repair spells... I guess so. Remember, tho, arcanes DON'T HAVE OTHER SKILLS, all they have are their spells. that's why, when they're out, they're hard to use.

4) Stats: +2 phys, -4 mental: determine randomly at creation. any phys stat gets a bonus. The mental stats: roll 1d6 twice to determine. They could have int, wis, or cha penalties, or massivly reduced other stats.
On top of this a regular -2 wis, due to their being CONSTRUCTS, NOT FULLY GROWN MINDS, as well as being especially mentally vulnerable.

Those are my ideas. I like the class, and think that the above should make them LA0. LA isn't good for PC races. In fact, it's really really bad.