@Midnight9746 
Yeah I guess #4 is more a problem in higher elos where the active numbers of players are quite few but I would not be surprised if it also would have noticeable effects on queue times also on mid elos. Blocking out the bad players is one aspect of the problem but more importantly; if everyone kept blocking people, the possible ways of forming 20 teams would decrease exponentially. 
Ive wrote this before but imagine if player A is blocking player B and D, player B is premade with C and is blocking E, player C is blocking A and is premade duo with F, player D is blocking F and B, player E is blocking A B and C etc etc etc etc then the it would become a huge web of ways that prohibit teams from being formed. Imagine if on average, every player had 50 players blocked among an active player base of like 2000 queuing for matches for the same ranked lobby.. It would be a disaster.