It's very nice to have more envelopes, more filter types, more of this and that... But even my old Waldorf Q (not to mention venerable Nord Lead) has drum sets as patches. It would be very convenient not to spend four or five timbres of TI just for drum sounds. Maybe just one timbre dedicated to drum patch, with at least six various sounds across the keyboard. It's even better option for Ti Snow 
Drum set for TI
-
-
The internal architecture of the TI doesn't support this, so it would have to be in some other product, not an upgrade. What people usually do is buy a relatively cheap sampler, design percussion and drum sounds in the Virus and sample them into the sampler.
-
Thanx for your reply, however, sampled sound is not the same as synthesized (as you know for sure). Well, I didn't know for hardware issue of the Virus, so I'll continue use it as a (great) source of synthetic sounds, AND spend more timbres on drums... Such a pity... They're sounding much better then on Nord, or even Q. As for samplers... They are just different (I have two of them, but their purpose is quite different, I'm affraid). Thak you again!