1. The app gap, maybe it's just me. I need apps like Dropbox, Duolingo, Youtube(I know there are unofficial apps around). Jesus Christ, developing for Windows is so much more easier than iOS and Android. Hope things will improve after Windows 10.
2. Consolidate the Setting page into something more concise and easily navigatable.
3. Faster roll out of firmware(especially those poor USA customer that are often bullied by their carrier). The OS update front is doing very well especially with the Developer Preview.
4. Better camera app. The upcoming Lumia Camera that comes with Denim update looks exciting.
5. The 'Back' button should suspend instead of exiting apps, so that we can fast resume.
6. Include Phase Detect in the future camera flagship. I'm looking at you Lumia 1030.
7. Make the Xbox Music app smoother and faster. Give us more 'Song Estate', I need to see more songs on that tiny list.
8. Tell us what the 'Allow App to Run in background does' in the battery saver app. I still don't know whether I should allow the apps or not.
9. Include explanation for everything such as, if I allow location to be turned on at all times, how will it function? Will it drain away my battery life and ping every few seconds?
10. MicroSD slot
11. Preferably swappable battery, 1 or 2mm thick doesn't matter to us anyway.
12. If the back cover is exchangable, then install no Qi-charging by default. I can fork out extra money if I want it.(This can reduce MSRP)
13. Rollout Cortana to every region in the world, especially countries with people that knows English(Like Malaysia and Singapore, we are Trilingual and are able to do 3 different English accents). However I know that for now Bing isn't really tailored to other regions, but I believe Satya will push Bing to the world eventually.
14. Use high quality AMOLED displays, the whites on current Lumia AMOLED isn't really white enough.
15. Give us an option to reduce the animations(flipping when opening apps and such).
16. Use high speed NAND flash memories so we won't see the opening... loading... words so often.
17. Teach developers to optimise apps to efficiently use the chipset.
18. High quality apps(Let's take Facebook and Whatsapp for a comparison, they lose out to their iOS counterparts)(Another example would be the LINE app, it takes ages to load and cannot support certain type of messages.)
19. Let us toggle data connection in the quick toggles. Sometimes when working seriously, I would like to switch off my data to ignore all notifications. Indeed, I can access the settings to toggle it, but having this feature would make one's life easier. It's the small things that gives a smile on our faces.
20. Stop region locking Xbox Video for customers outside of the US. Just give us whatever that we can have instead of locking us out. It's like WP user outside of the US don't deserve anything.
All in all, I was an ex L1020 user. I switched to an old iPhone 5. I'll holdout until next year. I just hope there will be a flagship that's worth it and Windows 10 will not disappoint. I yearn to return to MS. Please don't disappoint me.