There is no way this involves "a lot of code" unless they're talking about adding some overly complex way of blocking abuse with a cooldown on it or something, which is unnecessary. Later on, if they want to work on it some more and restrict it to the party leader only, or display who initiated the ready check in the popup, or add a cooldown, that's great. But all they'd have to do right now to make CT more bearable is to stop it from being used in combat.
In the event handler for the Yes button on the "Commence ready check?" popup, check if the player is in combat (using the same method the Vote Dismiss function uses to accomplish literally the exact same thing) and if they are, don't commence the ready check and display a red error message. Hell, they don't even have to translate the error message! Just use the generic "You can't do that yet." string.
I'm not expecting them to write the code, test it, merge it into the production branch, compile a patch, get it certified with Sony, bring down the servers, and deploy the fix tomorrow, just do it sooner than 4 months from now.