If TF2center had skill rankings, that'd be much better, and being able to set a lobby type meant for high level, mid level, or low level players only. The problem is, that there are a few people in those community who thinks it's fun/okay to just troll people, go on alt accounts, and be able to use those alts to stomp lower level players. I feel like this is a problem with Invite/high IM players making an open team just to stomp/win 1st place/etc.
I haven't heard occurrences like this happen much in CSGO or Dota 2, cause the people are mainly focused on their own ranking and want to improve. Not saying it's a MAJOR problem, but it definitely might be an issue to just have players stomping around, cause it can discourage players to give up, quit, and stop trying competitive due to those players.
It's probably happened already or still happening time to time. Even if we just lose those "few players", each player counts in our situation and it's immature to do so, which is one of the few minor things holding TF2 back a bit.
EDIT: Also, what about attracting players from other games like CSGO? Maybe have them learn about competitive TF2 and attempt at it or try it out. One way to do this is maybe to compromise with some known CSGO teams, have them sponsor a TF2 team, not maybe support financially, but have them on the roster and be able to use the tag legitimately, and give out info on it, and maybe get actually CSGO invite players to try out competitive TF2. It could be like 3 invite TF2 players + 3 Invite CSGO players vs 3 invite TF2 players + 3 invite csgo players, it could be like an event stream and the CSGO players could spread the word, gain viewers, and show others what competitive TF2 is like.