Not giving CE's the CIB is totally insane! The main mission of the CE's is mobility and counter mobility. Does it help to obstacles in the rear echelon areas? No! You kind of need those at the front. Where does one normally obstacles to take down? Yeah, normally find those at the front, too. And what does every boot-a** Lt learn at the The Basic School (a 6 month crash course on EVERYTHING following OCS in the Marines)? Obstacles without observation and fires covering it are useless! As I'm sure the Germans knew this, that pretty much means that the CE's were having to reduce obstacles (frequently mined or simply a mine field) while people were shooting at you or dropping artillery on you. Not an enviable place to be. If they didn’t rate the CIB, maybe there should have been a Combat Engineers' Combat Badge that was cooler looking than the CIB!
You know what the problem was, right? The Army was run by infantry guys.