Er, I find engineer is the EASIEST class to survive with. I solo dead man cave at lvl 16 on my eng (19 now) with no problems and no deaths thus far. Yes it's slower than my operative, but I can also do it without using any stims or power packs, where as with the operative I use a decent amount of stim packs. In fact the only deaths I have on my engineer are when I was soloing cycorp maps and I lagged out or accidently ran over traps.

A shield that protects and restores mana when up? A AOE attack that restores hp? A HOT spell that regenerates very fast? A spell that increases armor? 2nd highest armor class? Easy to survive if you ask me.