They basically crashed their own ship with "we need to control the player experience". Its so stupid that you cant join friends midgame, you cant have a larger party than 6, you cant join which team you want to make it more fair, but most importantly the personality completely disappears when you run a matchmaking system.
As for minding the "new" casual system, I like it less than I liked the old casual system and that wasnt great either. There was no need for this in the first place. Its sad that they used this kind of system to deal with the influx of players that were anticipated (and came) from the F2P patch in 2011. What they should have done is dedicated "valve servers" that you can access from the server browser to make sure there are at least some kind of not-modded experience and make sure there is always a leftover of servers for the players.
Obviously I understand the dev teams fear of what if someone joins a modded server or gamemode and get a skewered first impression but come on really? That wasnt a problem back in 2007-2010 where everything was ran by the community.
What pendji said has made me avoid solo pubs completely, I enjoyed it back in 2012-2013 but nowdays it is so life-less. Players have no reason to get to know eachother, no reason to feel that they want to improve or join a "quickplay community" (lol) because in the end it'll only be limited to the system. And the system is so bad it has effectively killed interest in public tf2 for me, personally. There is no fun or excitement in pulling off a master disguise, going for crazy sniper/rocket shots on players or trying ninja engineer shenanigans. 99% of the players are around the skill level where they cant even control their mouse let alone react to something happening 10 meters in front of them. Its like bullying bots.
Playing around a community would give you much more room to receive help, see what other players are doing, have more fun (the game gets more fun the better you get) and get to meet the good and bad guys. Instead of harvesting the future of tf2 pubs, we got quickplay. You reap what you sow.