Generally speaking, i think that even after a potential super-patch that might correct everything that's wrong with the sim, people might still be slow to pick up new habits.
I think that's the main reason, IL2 had a good run through the years, so everyone expects CoD to be IL2 with better graphics and some flight/damage model improvements.
CoD however is not that (and believe it or not, many actually like the change) and the departure from a long-ago established way of doing things is getting some people confused, some others annoyed and some even plain averse to learning a new way to do the same thing.
There are certain functionality issues and bugs but that's not what i'm referring to. As far as i'm concerned, even when the game is 100% functional there will still be some time before things pick up because people are simply lazy to learn new tricks
As for the question that will invariably pop up in such a discussion ("if it works why change it?"), the answer is again simple: to be able to do more in the future and not limit the game's engine to exactly the same capabilities as its predecessor.
Some added complexity is unavoidable in this regard.