Liking what I see
Some suggestions:
#1 Place some barriers or visual ques the players attempting to flank are not abruptly faced with red zones of death.
#2 Add extensions (static mesh planes/low res terrain) to perimeter of map so it doesn't appear that the playing field is a square board floating in space. Look at RSTE-IwoJima to see what I mean.
#3 Make a "fall back" area for the defenders so when the bunkers are taken they still have some cover and an opportunity to recap the last objectives. Again, Iwo is a good example.
#4 Either lower the arttilery counter or give the attacking team a few extra Squad Leaders to throw smoke, they're gonna need it