In my opinion +/-2 Tiers is not that bad, it is playable and you can have fun if it is variable. But there is much bigger prolbem. And that problem is if your matchmaking works only as +2 tiers. During last half year I made stats and this is how my matches are looking:
1 out of 10 battles I am against +/-1 Tier opponents. Playable game.
7 out of 10 battles I am against +2 Tier opponents. Playable game, not very enjoyable.
2 out of 10 battles I am against +2 Tier opponents and am the only one in team with the lowest tier (=I am T6, rest of team mates are T7 and T8). Not at all playable, no chance of enjoying.
Doesnt matter if I play alone or with friends. When I play with my friends they are frustrated that we play all games with above parameters.
This is a real problem as when playing hundreds of games like this is very frustrating.