There just isn’t enough motivation other than a few perks to taking engineering anymore in my humble opinion. Blizzard has been nerfing the hell out of tinkering for a long time now with grenade restrictions, stealth detection all but worthless on goggles, and now you can’t use nitro boosts in Arenas. It just seems to me that with engineering, you have access to all the fun “toys” and gimmicky changes that have real implications to the balance of PvP.

So you can play with these toys just don’t take them outside right?

After several attempts to balance the Nitro Boots ability in the arena, we have decided that we currently do not have an acceptable solution. Until we are able to better balance this ability it has been shut down in the arenas. We fully plan to continue working on this item and we intend to adjust it in upcoming patches.
We have plans to make certain that this item is still worth the investment made in it. So don’t vendor it just yet.