All accessable via the i button, of course
Adding a new required button is a deal-breaker. I have my Info button programmed to send a MCC command that shows the OSD now (the scrub bar). It isn't hard. Of course if you're lazy or your remote isn't very programmable, you could just program your i button to do a down-arrow keypress, which seems easier to me.
One of the things I like best about Theater View is that you only need to teach people about 6 buttons total. Up, Down, Left, Right, OK/Enter, and the Green Button. Period.
I think the way that MC's Theater View navigation works is absolutely brilliant, and the OSD is mostly-brilliant. I'll give another anecdotal example:
My parents came up about a month ago to visit for a week and serve as stand-in daycare, since our regular provider was closed for a few days. They were left alone at our house while we worked, and had to be taught to use my wacky TV system. I showed them both SageTV and MC. Since they mostly just wanted to watch Live TV (which we never do) they spent most of the time, early on, in SageTV. They were constantly getting lost and stuck in the UI. I even got a few phone calls while I was at work asking how to get out of some crazy menu they got themselves into (half the menus in Sage you can exit with the left arrow key, but half of them you need to use the ESC/Exit key, it is infuriating).
About half-way through the week, I showed them Theater View in MC again, and showed them all the stuff I had "pre-recorded" (as I explained it). They tried it out the next day while I was at work. I got a text message from my dad saying "Wow! We should have tried this before. This is SO much better!" (or something to that effect). Their only complaint was that they couldn't get to Live TV through it (because I
still haven't tried switching over again yet), but I have so many movies and so many TV Show episodes that they quickly stopped caring much (except for during Dancing with the Stars which my mom is addicted to, but that was in the evening so I could pull it up for her).
I like how you can easily access the OSD menus with just the up/down arrows. And I like how left-right does most adjustments immediately. I'm even not convinced about the Chapter Switching that rick.ca was discussing, as I typically just use chapters as "bigger FF/RW steps" (and I suspect that is true of most normal humans as well).
However, when you are changing an audio stream, subtitles, and other stuff like that, I think it is a bit discombobulating to most novice users simply because the expectation is that you'll navigate through a set of choices and then use Enter to select the one you want. Plus, when there are multiple stream choices, there is no way to know this from what displays on the OSD. It just looks informational. There's no visual cue that there are more choices available without "trying it to see". Plus, the fact that the audio skips when you switch them.
A simple way to address this would be to automatically pause playback when the user changes the audio stream (or whatever), and then when they press Enter, playback resumes.
A much
better fix would be to have these parts of the OSD be able to display a "menu" with more than one option visible at a time in some way. So, perhaps when you left/right (or Enter) on the current Subtitle or Audio Stream OSD items, instead of showing the different choices one-at-a-time and live applying them, it would then overlay a new 10-foot semi-transparent view over the video where you can arrow up/down and pick the stream you want from all of the available choices, hit OK, and then be returned to where you were in the OSD. The same menu overlay could be used for a bunch of other mid-playback functions as well (like selecting individual chapters, navigating through stacks, etc).