That's a probably plus, but the resolution of the digital signal via USB is rather limited (44.1kHz or 48kHz/16Bit) compared to what the TI2 uses interally (192kHz/24bit). Thus the Virus TI2 should offer much higher audio quality at the analog outputs, than what is actually possible from the digital signal via USB. Maybe what you perceived as "thin and brittle" is actually the additional top end crispness which is missing on the digital outputs.
BTW, I find the 16 bit actually prettly limiting, since clearly shows degradation on low volume signals such as releases or delays and reverb tails when boosted or highly compressed (OTT anyone ). Therefore I always record all the Virus sounds over USB at maximum volume settings just to have enough headroom for later signal processing.
Always a wealth of info
I have a Ti Polar V1. Thought there was just DSP update and paint job, any converter update you know of?
USB limit would be due to spdif spec, would need to be AES3 for 24bit. Excellent point and certainly a vote towards some hardware upgrades!