Pretty often I run into sounds made on other synths where the character of the sound is heavily influenced by the filter feedback amount. Depending on the amount, the effect goes from subtle darkening to serious muffling to total destuction (when the whole circuit starts to self oscillate), often in a very dynamic even chaotic way.
I couldn't find a way to acheive the same on the Virus TI, and would love to see a real filter feedback option.
Best would be if it was possible to choose the patch/insert points and if it could.