Altiverb runs in HTDM -- so for those with processor power to spare, this is not an issue. In fact, it's nice to off-load some DSP to the main CPU - freeing up TDM dsp for tdm only processing, and using HTDM for some waves plugs and altiverb.
I agree that iLok support would be a bonus.
I just finished mixing a project this week and used Altiverb extensively... quite satisfied with the sound I was able to get out of it and performance issues with version 4 are signicant improvements over prior versions.