Out of curiosity what functionality do you see missing?
The short answer is that Verizon is my biggest problem. If they sold a Titan II type phone I'd be much less apt to go back to Android. But they don't, so here's my list that I need to see fulfilled:
MS Improvements:
1. Mass storage mode - no argument of other options, see my past posts before you tell me I don't need this
2. Higher screen resolution - fairly certain this is going to be supported with WP8 from other news items, but I just love the clarity of the HTC Rezound for example
3. Navigation improvements - Bing Maps have been terrible for me as far as user experience and the directions itself, especially coming from using Android's Google Maps. I don't want to fill this post up with a long rant, so I'll leave it at that. If indeed they are going to be releasing a Nokia Drive for all WP phones, then it'll probably address all of my problems.
4. Voice recognition improvements - voice recognition isn't bad, but there is definitely some improvement needed to work as well as Android's voice recognition. I rarely had to re-say something for the phone to pick it up with Android....my Trophy on the other hand I've been frustrated enough that I ended having to pull over and type stuff in because it wasn't getting the simple phrase correct.
5. Non-marketplace app installs - This is what initially sold me to switch to WP as I read about the ChevronWP7 unlock tokens that allowed this. Except they weren't available and are now discontinued. This would have save a couple of grips from below (i.e. tethering and app folders)
6. App Grouping - There are a ton of apps I have installed and most I use quite frequently, but the list is annoying. I'd much rather just go to say for example a "news" folder then remember all the news apps I have installed. They grouped all the games, but nothing else.
7. Setting's shortcuts and scripting - I understand MS's position on not allowing programs to control your phone's settings, but then at least come out with MS's own live tile quick toggle buttons and location-based profiles. I find it annoying that I have to change my brightness, wifi, volume manually when I'm at work, home, or out for the evening. Again with Android, they had widgets on the home screen the 1 tap is all it took to toggle settings and there were apps that were easy to script your phone to do multiple things based upon some event like day/time or location.
8. IE Navigation - no forward button, seriously? Also the tab switching is terrible. They should be true tabs at the bottom instead of an address bar IMO.
9. Notifications - still hate that unless you look at your phone with in like 10 seconds of hearing a notification you have no idea what just caused it unless you have all your text, phone, email counts memorized...let alone if they ever allow apps to notify you of things like Android does.
10. Alternate keyboards - MS does have one of the best keyboards out there, but I'd still prefer a Swype type of keyboard as it saves me a lot of time pecking at the keys.
Carrier/Phone Vendor Improvements:
1. Screen size - Looking for a Titan sized device with higher resolution
2. LTE - obviously already supported by MS
3. Tethering - I used this feature a far bit while traveling and at work with my Android phone. If I could "root" my Trophy as easy I could my Android phone to get this, that would have been nice. I'd be surprised to see this feature put onto any Verizon devices like AT&T allowed Nokia to do on theirs.
4. Battery life - I was really hoping that WP was much better on the battery usage because of the hardware optimizations that Android didn't have, but that was not the case with the Trophy (yes, I know the 1st gen LTE Android phones sucked down the juice much quicker, but non-LTE Android phones got at least as good of battery life as the Trophy did). I put this item under the phone vendor list because I've accepted the fact there is no magic to eek out a 25-50% battery gain over another OS...just put a big battery in it (which I put an 1800 mAh battery in my Trophy and am satisfied with the battery performance of about 36 hours).
5. Better camera - not too impressed with the camera hardware in the Trophy.
6. HDMI out - not a huge feature, but I would love to have this for traveling, in-car navigation options, or a laptop dock like Motorola's or Asus's phone to laptop ideas.
To be honest, I've had a fairly good experience with WP thus far. I do enjoy my evenings not trying to tweak my ROM of my phone like I was doing with Android. So short of Verizon not releasing any WP8 devices this year, I'll probably stick with WP. But if it'll be next year, I don't know how much longer I can hold out.