I asked guildmates to talk me out of it. Before then, I was talking myself out of it. Although I'm on a regular PvP server now, I even considered the roleplaying implications. But it's time to face reality: Engineering really is not a viable PvE profession.
This +300-page monster thread on the official forums covers a gamut of opinions regarding Engineering. Some engineers doggedly persist in their profession, to cries of "Tinker Pride!" Others decry the whole profession as an unmitigated failure. Blue poster Bornakk insists that Blizzard feels Engineering "work[s] out compared to what other classes have for the time being." Meaning if you're not happy with engineering now, you should hold no hope of things improving for you.
WoW Insider wondered why, if this profession is inferior to every other, so many engineers are specifically threatening to take up Jewelcrafting. I think the biggest reason is because many engineers are also miners, and would prefer to level up one new trade skill that pairs with mining instead of a new production skill in addition to a new gathering skill. Another part of it may be that Jewelcrafting, with its rich array of BoP trinkets, feels more like what Engineering should have been in the first place.
For my part -- and especially as a tank -- I can no longer pretend that the myriad stamina gains from being a jewelcrafter begin to compare to being able to toss a frag bomb. Aside from Hyjal Summit, I can't remember the last time I'd have preferred a parachute cloak to a +225 armor enchant. (And even then, the goal was not to suck with your Tears of the Goddess, not to have Engineering save you.) I can't even use the Reticulated Armor Webbing, because it's limited to plate.
I loved Engineering, mostly because it was fun, and in part because it enabled me to do things I couldn't have done otherwise, like ranged pulls and powerful misdirects. But the hard truth is, the profitability and utility of jewelcrafting far exceed what I can presently eke out of Engineering.
And so begins another grind. Sigh. 269 JC and rising...