I don't see any issues that would prevent starting a CFM. If you play the preseason, you will see any bugs that would make a CFM not an option for you until something is fixed. I've played a pre-season and didn't see any big concerns. I restarted only because I had accidentally used a bad roster where Fitzpatrick was a free agent and signed with Cleveland.
Right now the only 2 bugs I see that are an issue, have already been addressed and will be fixed in the first patch. Until then, they are easily fixed by enforcing some "house rules". The 2 I'm referring to are the bug where you can see if your opponent is running or passing, and the bug where you can see all the stats for guys in the draft class, before the draft. As long as you can trust yourself to not use these exploits, then I'd say start it up!