To your list, I would add being able to manually adjust front/back focus for individual lenses and store these settings such that you can bring them up for each of your lenses. I know this is not much to ask...because it's a feature of the K20D.
Would I pay for these upgrades? Hmmm...maybe I would, although I think it would be a nice touch for Pentax to make them available for free. For those who say they would lose money, I disagree; how many people are going to upgrade to the K20D
just because of a few firmware upgrades? Not that many, I'm sure. If you decide to upgrade it will be for other features that have to do with the hardware, rather than the software. Plus, updating older firmware when new models are released is the kind of thing that makes current customers
really happy; and there's no better publicity that happy customers.
As a side note, back in the late 90's I used to have a Boss effects pedal for my electric guitar. It was an awesome piece of kit, with better build and sound quality than the competition, but it was not as popular because the other companies spent a lot more on PR (does this sound familiar?). Anyway, at the time manufacturers were starting to realise the potential of being able to hook up your music equipment to your computer and the leading pedal in the market came bundled with a software program that allowed you to control the pedal via your computer. Not only that, but it added functionality and versatility that you just couldn't achieve with the limited buttons on the unit itself. And what's more, they had set up an online forum where users could exchange effects settings in small files, and there was a repository for them, so if a novice wanted an effect to sound like Jimi Hendrix he could download a patch and was ready to go. All this was free, of course.
Boss, however, had no such software, and they were losing customers because of it. I thought they would work their arses off to create such a software, but they didn't. So, some smart guy saw an opportunity and wrote the software himself. It wasn't as flashy as that of the competition, but it worked extremely well. He sold it for $25 I think, and every few months he would release a free update. As you can imagine, it sold extremely well.
Yes, there is a point to this loooooong story: Although we would like Pentax to keep updating their old firmware, they are unlikely to do so, and if someone is capable of offering an alternative firmware with these desired upgrades, there will be plenty of people willing to pay $25.
I'm not sure about the legal ramifications of selling modified proprietary firmware, but I'm sure there would be workarounds.
OK, you can all wake up now!