What I requested is an "Application Level Firewall" where traffic of different applications can be detected and then blocked as per the defined rules. It is fine if MikroTik cannot release signatures for all the different applications out there or keep updating them, what we need this functionality to be available in MikroTik and let the community develop the signatures for whatever applications they want to detect and block. MikroTik community will happily do it.
I have to disagree. Poorly-maintained definitions can be worse than nothing at all. If users think they're covered when they aren't... And there are some sharp cookies in the ROS community but it's not nearly large enough to say with reasonable assurance that the community has all bases covered. There are many community-supplied recipes/howtos/etc for ROS that make me cringe. For example, there's a firewall recipe that includes blocking bogons, but the bogon list is YEARS out of date, and I still see people posting their firewall configs here which are copy/paste replicas of these rules.
An un-maintained signature database for this would be like your doctor working from the leading medical journals from 1997 or something.
If you argue that an app-level firewall be implemented as a module which can be activated/removed then I would say this is the way to go. I personally wouldn't use it because I see no signs that Mikrotik has the resources to dedicate to maintaining such a service on the level it needs. ROS is quite a wonderful system but it still requires much improvement in its core functionality. Bells and whistles would be too much distraction from this IMO.
Granted, I'm talking about security vs something that just dictates policy like "no Skype allowed" which you actually can do with L7 filters. (This is their original intent, not web site filtering) and you could even use recipes from the Linux/netfilters community since it's the same thing.