Well, first of all I think the gameplay need some major changes (something like ProMod comes to mind). AFAIK BF3 has already a match system where everyone has to ready up before starting a match (I remember it being used on many ESL matches).
RoundTime and
Pause functions are needed, the first one is a must for Squad Rush mode (iirc camping attackers were a problem), the second one is needed in case of crashes and not only that.
Spectator mode definitely need improvements, I'd say bringing it on par with the BF4 version would be a good start, naturally I'd suggest to go even further a bring it on par with what CS:GO has (if possible)
Oh and what about a battle-recorder/demo-recorder? Is any of that possible?
That's it for now, I'll add more later if anything comes to mind
E1: a competitive matchmaking too wouldn't be bad.