Just to give my own personal two cents, I think the value of general-purpose live tiles or widgets is supremely overrated. There are a limited number of cases where the value is immediately apparent: Weather, calendars, communications (email, texts, whatever), headlines.
Beyond that, though, I think it starts getting a little overwhelming. I don't really feel the photo collages in the People app on WP7/W8 add a lot. I think some stuff, like games, are just an unmitigated disaster. No I don't need my high score flashing. And it's really really terrible to watch a big grid of Live Tiles all wobble back and forth, like watching all the flashing ads in Times Square or news stations with multiple tickers scrolling at separate speeds. It's visual clutter.
I recognize that there's a tweaking element that a lot of people enjoy, but I personally prefer a strong design vision. That's not to say I don't want any flexibility. I don't care about the weather and I'm glad I can remove it from Notification Center. But I don't necessarily think that full visual customization works to enhance a product. I think most services and products with full skinning systems allow a subset of users to indulge themselves in a way that actually makes them ugly and less usable. Twitter and Facebook versus MySpace, for example.
Going forward I think Apple needs to do better with Notifications, and I think it'd be nice if they could convey more with the home screen and lock screen. But I don't think I'd like a move to Live Tiles or widgets.