Having dynamic EQ built into Pro-Q 3 is truly fantastic, but it's missing the ability to key your dynamic bands based on an external sidechain input. This is incredibly useful, both for sympathetic dynamics to help things groove together, but also for surgical mixing, and I'd love to see it implemented into Pro-Q 3.
I can understand, however, that it may seem like it's encroaching on Pro-MB's territory a little bit, as the multiband is capable of external keying for its bands. Even with this overlap, people reach for multiband dynamics plugins and dynamic EQs to achieve different goals. To that end, it would be great to include in Pro-Q 3, just to lower the impedance mismatch.