For engineering to be both competitive and for goggles to be viable tinkers that provide secondary stats need to be added as recipes. They can be behind renown grinds. The tinkers really just aren’t good enough to replace all the stats lost for pve nor pvp. If they were you’d see peoples profiles in murlok using them and you don’t see any for pvp not pve.
If there was a tinker that provided an effect like the lariat, or like the unstable frostfire belt, or like the blue silken lining, etc maybe. It’s far easier to at least give tinkers for haste, mastery, verse, or crit.