I agree, the proposal for Phase III does not solve some of the [strike]endemic[/strike] systemic problems - no real dedicated lane in the South End (has to stop at stop lights, has to go around cars) and a mind-blowingly slow ride from South Station to the airport.
I do, however, think it's the best of all options, if we are going to continue the Silver Line bus line. Yes, adding buses to Route 28 would work to a certain extent, but let's deal with what we have and make it better.
I haven't timed it yet (has anyone?) but I am guessing that, the Blue Line is faster to the airport right now, and probably will be, even after Phase III is completed.
A good use of federal stimulus funds, in my opinion.