Comodo's focus is not virus signatures. Their AV component is only one of the layers available in their internet security suite.
From what I see, Comodo does not place a primary focus on shielding a system via anti-virus, anti-phishing, and malicious URL blocking. While there is nothing that one can do to bolster the AV module, one can import phishing and malicious URL blacklists.
The real strength of CIS is how it can cope with apps once they are on the system. More specifically, the Behavior Blocker, Sandbox, HIPS and file system policies do a solid, if unspectacular, job. As Cruel Sister states "they're a beautiful thing." In short, with CIS you are generally protected if you run malwares sandboxed or within the Virtual Kiosk.
Comodo has its own approach to solving the supposed problem of the obsolete AV signature model...
I wouldn't be surprised if the AV module goes by the wayside at some point in the future.
I think CIS is unjustly maligned and under-rated. As of yet, I have not seen a truly thorough review of the Virtual Kiosk. On top of it all, it's pretty darn solid for a completely free product (all you need to do to make high-level use of it is not to forget to read the 600 page User's Manual).
Let's face it...Comodo Internet Security is damn powerful, and therefore, it ain't for amateur night.
However, here is the rub...
CIS, with all it's layers of protection, with all it's additional complexity, (and with all it's confusing bugginess)... provides me, on my specific system, no greater level of security than this simple-to-use combination: Emsisoft Internet Security or Emsisoft Anti-Malware + Shadow Defender.
Call me quirky...but simple is better, ...much.
Alas, Comodo ain't goin' downhill...Melih's just going his own way.