Here is my list of improvements/suggestions required in WP8

Better Multitasking

With WP8 multitasking has been improved a lot, but still the instant resume is not quick enough.

There always this resuming screen which is being displayed, this has to fixed the apps should resume instantaneously PERIOD (Win8 is really quick to resume apps, if they are based on same core why can't WP get this right)

Kill the capacitive buttons

Another issue with Multitasking is the gesture to display the multitasking cards. Looong press the back button is not intuitive. Also two conflicting actions for same button doesn't count as a good design (There many instances where i closed an app when attempting to get to multitasking cards). And there is this annoying search button which accidentally kicks off bing app a gazillion times. Capacitive buttons are most annoying thing in the current WPs, kill them and replace with Win8 style edge gestures.

Windows 8 integration

Windows 8 and WP are like two brother who look alike but they rarely talk to each other (Think about it we can send a website from IE in WP to Xbox and Xbox to Win8, but we cannot send it directly from WP to Win8). Microsoft has done a very poor job at Windows 8/WP integration till now. Possibilites are end here, here are some basic scenarios I can think of

I browse my twitter feed on phone and open few tabs and when I get back to my desk with a single click all those tabs should be transferred to Windows8 (Also we vice versa) Sync IE history, bookmarks, stored password, etc Start to compose a mail on one and finish it on another. (WP doesn't sync drafts with cloud) Wireless Sync (Was present in WP7 not sure why they removed it in 8). All my favorite music, pictures, etc should be transferred from my PC - Phone (And without any Xbox music pass, etc) Common App store, when I purchase an app on phone it should automatically installed on my PC (Of course if I enable this) Games - We have seen tons of demos where I can start a game on Xbox and continue it on my phone. This has to gone main stream, at the minimum every premium Xbox Live Game should support this. WiFi passwords - I have stored my home n/w wifi password with Windows 8. So why cannot WP get this info from its big brother instead of asking me (Win8 already syncs WiFI password between different windows 8 systems).

Notification Centre

I'm not a big fan of this, but I know may users who need this feature.

Settings

One of few things in WP that is very poorly designed. The infinite list with no icons and sorted in particular order is always a pain, redesign this page add some icons, give our muscle memory something nice to remember.

Secondly we need quick access to frequently used setting like Wifi, Data connection, etc. At minimum allow to pin settings to start (I know there are 3rd party apps which can do this, but we need something built in).

Volume Controls

Same volume for my music and alarm/phone?. BS, give us different volume setting for music/phone/alarms.

Universal Search

Need something similar Win8.

Share

Support share contract similar to Win8

File Picker API

One of the best features of Windows8, allow apps to share data with each other (i.e., I should be able to upload my photos in box storage to FB using facebook app). This also solves the problem that we can only add photo attachment from *inside* the mail app

Voice Assistant

Start Screen WP has most useful and beautiful home screen on any platform. But it can be better, one feature I can think is give us option for multiple start screens. i.e., Add more start screen to left/right side, this will allows to have to groups live tiles/apps.

Built in App improvements : Phone

Even after 3 years the phone app is still barebones, lot of improvements are needed here.

Smart dialer Why the history page is not grouped by caller? For all the calls older than a week. WP only displays the date not time. There are many instances where I wanted to know the time I called a particular person but I simply cannot. Because WP team thinks that info is useless. History search is also useless. You have to remember the complete number (including country prefix like +91) to do a search. Why does your stupid search algorithm use startsWith?

People This app can serve as perfect twitter replacement for most of us only if it can fetch more 200 (or so) tweets. Infinite scrolling in this app is broken from Mango release, fix it. There are many times the app loose the position when fetching new tweets. Why should I do FB contact linking separately on Win8 and WP? Groups, they doesn't get backed up in cloud. So whenever I reset/replace the phone I have to configure them all over again. Me Tile Push Notification. Background agent running every 30 mins to updating this tile is not good enough. Internet Explorer Background loading of tabs - I'm not sure why the heck this restriction was added in WP8 tabs are not loaded in the background (This used to work perfectly fine in Mango). WP designers have to figure out how to give me both tabs and refresh option. Have any one of them annoying. It will also be nice to have a full screen mode. Cloud -- We are 2013 please sync with favorites and browsing history with cloud. Win8 already does this keep it in sync with my Win8 When I pin a website to start screen please use favicon not the screen capture which is useless 90% of times. Website preference - Currently the option available is to render all the site in either mobile or desktop mode which is pain. There are few sites which we always want to render in desktop mode and others in mobile mode (For Ex: TheVerge doesn't work well in desktop mode and I always want to render this in mobile mode and IMDB mobile site is crap so I love to always use desktop version), give us option to set preference for each individual site. (May be something similar compatibility view mode in desktop IE) 6 tabs not enough. Messages Provide API to add support for other chat services. Mail Easy access to folders. There already a option to select mails by clicking on edge of the screen. So why don't you replace this with some other option? Windows Store Purchase history right on the phone, no we cannot fire up IE to do this. Option to reinstall all the purchased apps with a single click Photos So when I pin an album to start screen, why don't you give it a nice live tile (Instead of showing a static boring most recently added image)? Also no option to make it double wide. How about to cycle all my favorite photo as lock screen wallpaper? Give us some more editing options.