I would sure love to see better mirroring options as well. It's the main thing holding me back from upgrading my Vip722. I have 7 TVs scattered throughout the house and very rarely need to have something different on one of them. It's just my wife and I, so I wish there was a better way for the Hopper to mirror what's on in the living room to one of the other TVs without the additional expense and complexity of multiple Joeys.
I know it's not very likely, but I would love to see the return of a built in modulator. I know HD modulation is a pipe dream, so I would be more than happy with the SD variety. I'm not convinced that plugging my own outboard modulator into a Hopper will yield the quality and reliability of the one that's already built into my 722. Maybe I'm missing something, but I just feel like upgrading to the Hopper will cause me to lose functionality that I have with my Vip. I know I would gain a ton of new features, but this is a glaring issue that makes it difficult to pull the trigger. Our bill is too high already; installing several Joeys for TVs we may not even turn on for weeks at a time just doesn't make any sense.