Adding a direct front-panel interface for sub trim would require at least one extra IR command, so I'm not sure that we're likely to see that added via a firmware update. A small display in the rack is certainly one solution. I'd also suggest a couple things before you go to that extreme. First, try playing with your front crossover setting to see if a lower setting lets the sub integrate better with the mains (this was a problem with my old sub and house, and I had to use a 40Hz crossover to get smooth integration for music). Second, try the two-channel sub offset (which is essentially a separate sub trim for two-channel modes that reduces the sub's output in those modes).