I read through most of the posts on "SWAT are useless thread", and have seen repeats of the same for a while here.
OK--honest opinions from LEO's and others:
Should there be Local Control of the situation--the SWAT senior guy on the scene, or the "brass" back at the police station?
I can see problems with both scenarios--
The SWAT leader on the scene may push it too far, and you run into a "Ruby Ridge" scenario--Shoot the people you see, even if they are not a threat. Or, he gets a possibly erronious report of an officer down, and has everyone go in with guns blazing--in the end, the bad guys killed, some hostages shot, and possibly some officers now shot also.
The Brass may wait too long--fear of lawsuits, looking bad in the press, etc, may keep the officers out of the building while people are dying.
I would venture a guess that a happy medium may be the answer--a non-SWAT commander on the scene that calls the shots. He trains with the team to see their capabilities, but is not allowed to go in with them. He can balance the needs to keep the people in the building alive with the need to keep the shooting to a minimum if that is what is indicated. He has complete control locally during the situation--no outside interference, but he has to answer to the brass afterwards. They (more than one is needed) are on call the same as the SWAT members are, and are expected to show up at the scene when the team does.