Take issue with a couple of points
Ignoring your one (non-native) example I've found Metro to be delightful. Andrew - can I suggest using the native / integrated twitter client on the people tile?
The WP start screen has 8 tiles, then a further 8 as you flick down. Rinse and repeat.
The tiles are essentially widgets - and I don't recall ever having more than 8 per home screen on my HTC Desire. As you can have whatever you want I disagree with your comparison against other platforms.
Retail placement is Nokia, not the platform developers issue to resolve.
Regarding the spec being loosened I'm of the understanding that MS are working on this with the Tango and Apollo builds out this year. Dual core support, higher resolution, NFC and other features.
Whilst it has its issues I'm happier with my 3 month old Lumia 800 than i was my Desire. Loved playing with new ROMS and nothing beats Android for customization - but a reliable, solid device that requires no task manager, doesn't need me to "manage" my storage or other fluff - well I'd take a WP7 over Android or iOS as it stands right now.