I think that getting help with team management issues is as much of an acceptable request as asking for suggestions on how to build a 4-motor drive train. It just has to go in the right forum. (*cough*
http://www.chiefdelphi.com/forums/forumdisplay.php?f=86 *cough*)
As cliched as it might sound, you can't make people come, you have to make them want to come. By kicking people off the team, you accomplish nothing. Instead of coming to 50% of the meetings, those people are now coming to 0% of the meetings. If people are not showing up, the only way to fix the problem is to address the source; why aren't they coming? Common causes I've seen are being too busy (perfectly understandable at exam time, and cured only by waiting), or apathy (in which case there needs to be some activity on the part of the team's leaders to help fix it).
If one person seems to be "taking over" the team, the first thing to do is to make sure that is actually what is happneing. Someone who feels "displaced" by someone will naturally resent the other person, but having one person who is exceptionally smart, talented, or motivated take on a greater than average share of responsility should not be viewed as something horrible, rather, it is inevitable, even in the most egalitarian teams.
However, if the person is going
too far, that may indeed be cause for concern, as a bottleneck can result in slowing everyone down because 30 people are trying to get approval from 1 person with limited time, or even worse, when that person gets sick and can't make it to a meeting, resulting in a whole day wasted. At that point, it probably is time for someone (a teacher/mentor or a senior student (but only 1 or 2 people, not the whole team)) to talk to the person and explain the situation and propose a solution.
I'm happy to say that our own team is suffering from no more than the usual, as predicted (2 students fell in love over winter break, 2 friends had a bit of a fight today, and 3 people have quit).