Engineering has never been about performance...it's always been about utility. I took engineering on my paladin pre-WotLK because I wanted the goggles. I made the new WotLK goggles and wore them from level 77 when I went prot right up until I got my T7.5 helm. Now, I'm restricted to make guns, Scrap Bots and (if I were so inclined) smoke flares to mark positions in raids. That's it, and to be honest I've been carrying the same 5 scrap bots I made the day I got the schematic in my bags since...the day I made them. I've still got 30 of the old repair bots waiting to be used up first, and we've got 3 tundra mammoths in the guild so the preferred repair option is to just put up a mammoth at the stone after a wipe so people can repair and also stock up on top tier reagents.
The gear augments offer nothing worthwhile for tanks, the guns do a pally no good at all, and the damn flying machines are too noisy. I finally got Exalted with Alliance Vangaard so I can pick up the schematic for the Mekgineer's Chopper, but damned if I can motivate myself to spend the 240g right now.
Srsly thinking of dropping engineering for another profession, but I'm not certain I want to go through the hassle of leveling another profession from 1-450 right now. It's still early for information regarding 3.1, but I'm not expecting much. Maybe an upgrade on the goggles like we saw with the Sunwell goggles...I'd be reasonably happy with that, but not until I had enough T8/8.5 gear to replace my current T7.5, because I don't want to sacrifice the 4pc set bonus for a minor stat upgrade.
I think it would be neat to see engineering weapon or shield augments or something else that actually improved my combat performance. I'm not holding my breath, though.