I think the following are the issues with CQC as it stands:
A) Matchmaking is, on some level, broken. How much of this is down to coding problems, and how much is because of the system struggling with such a small playerbase, I have no idea. Whatever the balance, the results for first-time players speak for themselves; you spend ages waiting for a match, and when you do finally get a match, you're highly likely to be thrown into an arena with much more experienced opponents, who may or may not take your lack of experience into account. I suspect that this is a highly discouraging introduction for many new players, especially those who are unaware of how third-party platforms are being used for organising matches in an attempt to circumvent CQC's shortcomings.
B) Lack of stability over multiple matches. For whatever reason, CQC has a distinct tendency to cack itself when played over multiple matches (the infamous "matchmaking error"), which adds additional unnecessary tedium to the process.
The matchmaking system to be significantly altered, or replaced with something that is agnostic to the total number of players online at the time, such as a system that assigns handicaps and/or advantages depending on the relative experience levels of each player in any given match. The stability needs to be improved, as part of a wider QoL sweep over CQC in general.
After that, we would then be in a better position to determine what if any other features need to be altered, removed, or added.