The only thing I would do to improve SWAT, aside from adding some extra, more close-range maps (Okay, I'm a battle rifle user), would be to add a compass. The maps are too confusing during a firefight to get any accurate bearings without a compass.
For example, Solace has a 'dirty' base and a 'clean' base separated by the thing in the middle. So, these are our landmarks. Problem is, the only way to spot the difference is to actually investigate a base first. A compass would solve every navigational problem there is. That way, we have North Base not Dirty Base, and on the more circular maps, you can guide your teammates using logical directions, instead of yelling "That bloody ramp over there."