Well in BOB'06 they changed the way radar stations showed up. Instead of bombing the tower itself, you now had to bomb the electronics building, and they'd have the huge wide antenna arrays, not the single tower. It was a custom object addition and would have looked sweet (from what I was told). However it was not done in time for BOB'06 so we used the original '04 map. I'm guessing the "facelift" is finally getting these new custom radar towers built into it and getting it out for everybody.
They never came out, but I know they were done, so I think that's the major change.