Not sure if anyone else has already thought of this, but what if there was another tool the engineers had that allowed them to hack turrets, terminals, (and pretty soon vehicles) just like the infiltrator? This new tool could take the place of the repair tool, so it would inhibit engineers from repairing vehicles and MAXs, but would give them more toys to play with.
So...give engineers not only the ability to use sniper rifles but the ability to hack too? What are infiltrators?
As an engineer main, no. Duplication of primary class abilities between classes throws a ginormous wrench into any attempt at balance. Engineers already have the most toys to play with of all classes, and while I wouldn't say no to more, giving Engies something from another class would be... rather disheartening to players of that class. If Engineers need a hack-ish oriented toy, i'd say that the ability to repair destroyed terminals (of other factions) might be appropriate, provided it remained under control of the faction that owns the terminal (meaning that it would need to be hacked by a friendly infil prior to use)
I think this makes the most sense, as it would crimp the whole "I blew up all the vehicle terminals past this lattice point, NANABOOBOO" tactic.
The Engineer has: Tankmines AP Mines C4 Turret Ammobox Carbine of LA Pistol RepTool .... And now that dude should can hack?!?