Ok, as someone who has been playing on it a lot, I do have mixed feelings regarding it, but believe it has the potential to be amazing.
Starting off with the matchmaking, there are the same issues that the current default Ranked MMR system has, and that is mixing solo players with parties, they NEED to make it SOLO queue, and TEAM queue. There are several reasons for this, but one of the main ones is because it's too easy to carry someone in FACEIT. When I say "carry" I don't mean in the match, I mean in the Ranked Leagues. There is no Solo/Party difference, so you can have terrible players high on the boards just because they play with 2 really good players that can carry them. The other reason, it makes it fair, there are times when you will have 3+1+1 going against 5 solo players, and it's horrible.
Next I would like to address the current issue of toxic players. I think part of this has to do with people being able to play on FACEIT while in low priority for intentionally feeding, but mutes still apply in their matches. My most recent incident was when I won a game, and in my next I was teamed with two people who were friends on the other team...That game ended quickly, and they were absolutely horrible people. FACEIT currently has a report system, yet I don't believe anything is being done with it any time soon, afterall they are still just getting started. People find people they don't like, and pretty much just have a mission out to ruin their games, since there's no real consequence for it since the reports don't really work in the matches (to possibly send someone to low priority or communication abuse) and they don't run the risk of losing anything since most of these people aren't even playing for points in Ranked Leagues (sadly some of them are because they want the chance of getting Captain so they can troll people from the start with the draft).
The short version, they need to change how Matchmaking is done, they need to change how the Captain is decided, and they need to start punishing players ruining games. It's always the same ones, you get an hour long ban from queueing if you dodge, but people will suffer through that just so they don't have to deal with them.