The wrench is there to simulate field repairs which IRL would mean taking the vehicle back to base then do any manner of fixing. From replacing tires to pulling out tanks engines. I dont think many people would like it to be that realistic. So we have a wrench.
Also there are a lot more things that can be fixed with a wrench than can be fixed with a torch. If you asked a Military mechanic I bet they'd tell you they use wrenches a lot more than they use torches.
resuggestion, however, good suggestion in my book. I suspect the Wrench will be one of the last vanilla thingys to be cast out and replaced with somthing a bit more suitable for PR. Its only a matter of time.
I think it would be better to RTB for repairs just like helicopters. I don't find somebody working on a tank in the middle of a battle realistic. Don't they usually just destroy the vehicle or salvage it after the battle?
I do think the wrench looks out of place but I don't think there's anything it could feasibly be replaced with... The welding thing just seems like it would take a lot of effort to put in and tbh doesn't really make a difference to gameplay
On a side note, perhaps they could make it so that a field engineer could only repair a vehicle to 50% of it's max health so that it could operate but would have to go back to main base to fully repair - not sure whether that's in game but it would be nice if it wasn't
I like the idea of a 50% max field repair, this would make the crews think more about the vehicle and where to use it. Also it would put pressure on commanders to use their squads in the right places, not just sending armour in to cap flags.