You are arguing that it is better for Massachusetts to have only one vote in the Senate, when we are allowed to have two.
First... yes what happened in 2004 was done only because the State legislators (themselves predominantly Democrats) didn't want a Republican governor to appoint a replacement for John Kerry should be be elected. They were able to do this because voters in Massachusetts elected predominantly Democratic legislators who had this ability. Whether this was "gamesmanship" or not is an interesting question-- but this was done by democratically (with a little d) elected officials.
It could be argued that what these democratically elected officials did in 2004 was irresponsible, but that is another question.
Right now the question is whether we Massachusetts citizens are better served with two votes in Congress, or with only one-- particularly with important national health care legislation which most of us support hanging in the balance.
The State legislature has the ability to change the rule so that we will get our full representation in the Senate. Most of the people that the State legislature serves want full representation in the Senate.
Ted Kennedy himself made a plea that his seat not go empty in this critical time. His compromise seems reasonable.
We should, as Ted Kennedy suggested, appoint an interim Senator who will not run for the seat when the election is held. This avoids an unfair advantage to the person is appointed without depriving Massachusetts of its voice in the Senate.