In WotLK engineers had a dps tinker for gloves, and the potential for a dps belt tinker if you were melee. Later on in WotLK engineers finally got an enchant combined with tinker for the cloak and boots which finally allowed engineers to not take a dps loss for using rocket boots and a parachute cloak. So mid-WotLK engineering was still a weak profession. It wasn't until late in WotLK that tinkers stacked with enchants that engineering became OP...post 4.0.1 does not equal all of WotLK. In fact it means virtually none of WotLK.
Now fast forward to Cata. Parachute tinker stacks with enchant on the cloak so we don't take a dps loss there (no gain). Glove tinker stacks with enchant so we get a dps boost there. Rocket boot tinker moved to the belt along with all other misc tinkers so you get rocket boots or melee dps could use the old WotLK frag belt.
So no, engineering was never 'go to' until 4.0.1 through Cata launch. Considering that engineering isn't a min/max profession it would be nice if the boots wouldn't fail in raids/dungeons. I can't tell you how much it sucked on HLK25 pre-Cata for boots to fail.