Why is it "...just retarded..."?
The weapons racks die in one shot, building them takes time and you are completely vulnerable 90% of the time. Knocking out a siege camp isn't really any harder than taking a wall. The real issue most people will face is that as more people learn engineering and use it as a class teams will start to work around them and use them to the full out of instinct and then the disorganised pubstars trying to take on the semi organised side will get slaughtered, but that's no worse than when a large clan like the Hospis come on in full force using team speak to abuse each other into higher level of performance.