As one of those raving HN'ers (although not an MS employee) who now uses an iPhone, all of those things you mention are legitimate issues, and I don't know many WP owners who would disagree. The real heartbreaker is that even with these seemingly show-stopping issues, WP combined with Nokia hardware is so good that it's hard to turn away from. Even though the software has so many issues that have been unresolved for so long, it's still that good. It was a tough choice to give it up, I only did so because it had let me down on more than a few occasions where I really needed it.
The last time I found a mobile OS that instilled that level of "so good it doesn't matter that it's bad" was WebOS, and I frequently compare the two. Unfortunately, I see the same future for WP as what WebOS got.
This was the feeling I had when I had played with the recent versions of WP. It felt like a fantastic OS, and the hardware ran it brilliantly.
My own personal showstopper isn't a fault with the OS, but with how the phones look. Nokia just seems so far behind in terms of designing an attractive phone.
If Nokia were to release a phone that looked as nice as my Galaxy Nexus, had a large screen, and didn't cost an absolute bomb I'd probably go for WP over Android.
I'll have to disagree with you on the design aspect. In my opinion Nokia N9 has been the nicest looking and feeling phone ever. When you have it in your hand the finishing feels great, especially the subtly curved screen that has deep enough blacks that blend into the black borders seamlessly.
Personally I loved the design of the phone most of all (plus how rugged it is). I got the iPhone 5C when I switched because I like the feel of the high quality plastic better. Unfortunately the iPhone isn't quite the same; it's slippery as hell and the colors are more pastel than the bold colors of the Nokia. In my mind the Lumia 920 was the best designed phone I've ever seen, but obviously that's just one man's opinion.
The last time I found a mobile OS that instilled that level of "so good it doesn't matter that it's bad" was WebOS, and I frequently compare the two. Unfortunately, I see the same future for WP as what WebOS got.