Otter, Xenon is right. Accepting fewer logical inputs is part of the trade off of using the 975. It's a low priced option and that's one of the reasons. It looks like the upcoming 976 is going to offer more. I think there's like a dozen input buttons near the top of the remote but we'll have to wait and see what the specs are on that. If you need more, you'll get a discount on the price for owning the 975 and then you could probably sell your 975 to help recoup some of the cost of the upgrade.

I'm mulling over doing that for the 976's big brother in another year or two. Right now the main issue I have is the same as you, I'd like to have a couple more logical inputs available. I accepted that limitation when I bought the 975, though. At the time I really didn't need any more but I have a couple of additions to our cache of devices and would like to be able to assign them all their own inputs. We don't have a 4k TV yet and there's not much likelihood of us putting in Atmos in the immediate future so upgrading isn't a requirement for me yet. It's definitely on my wish list, though!