Please take Black Shield out of IB Clash. Without an objective, teams turtle up in the center room and establish a death grip on the match. This is particularly true of match-made teams going up against a pre-made team with voice communication. Ultimately, these matches reach a stalling point where the internal team won't come out and the external team stops challenging and everyone just waits out the clock. Needless to say, it's not a fun way to spend my time.
Black Shield is a true kindred spirit to Firebase Delphi (the best map in the game).
Both are completely misplayed by most of the people who play them, but both are really tactical if you want to take the time to master them.