We should be able to allow people to pay once for our apps and then they can get both version of our apps for Windows Phone or Windows 8 without having to make them pay twice.

Viber is an extremely popular application similar to Tango, but better in some ways.
It has more users -> more people to call.
The application is built into your contact list (no application to open).
You can text people using Viber.

Here is the info thats available on the Website of Viber:
Viber is an application for free international calls and text messages to other Viber users using 3G or Wi-Fi. Uses your existing contact list - check out which of your phone contacts and friends is already on Viber so that you can call and text them for free.

As app developers we are currently stuck with 2 methods of generating revenues 1) one time app payment 2) Ads.

I would like to see a monthly/yearly subscription model introduced that let me charge users $5 a year for my app for example.

This would mean we could make ad free apps that developers are motivated to keep adding features to over time since they are generating ongoing revenues.

The following additional fields should be added to the crash report:
Date of crash
Phone model

I spent so much time and effort making an awesome app with almost 5 star averaging rating, yet there is no option in the Marketplace to sort by Top Rated so that people can easily find it ?!
Please add a Top Rated list ASAP!

Currently, there is no way of knowing if a user converts from our own advertising campaign or "out of the blue". It would be great if we could link to an app's store page with a campaign code, and get the breakdown by campaign codes in our daily stats. For example:

United States Paid (after trial) 32
United States Paid (after trial, campaign XYZ) 64
United States Paid (without trial) 16
United States Paid (without trial, campaign XYZ) 48
United States Trial 192
United States Trial (campaign XYZ) 284

Currently, you can submit an app to all countries, or specific countries. I would like a button I can click that will only select the countries for which Microsoft already accounts for any taxes.

When searching in the market you should be able to open the app if already installed.

Although you can subscribe to podcasts I cannot find a way to force a podcast to check for updates. Even if you see an update is available in the market there is no obvious way to force a podcast to update.

There is currently no indication that an application is being featured, it would be nice to receive a email prior to it being featured to indicate what dates / countries it will be featured in.

Many small developers skip Brazil and Korea from worldwide distribution because there are mandatory rating agency requirements.

Unstable loading, page layout glitch and too slow response.
Hard to understand error messages.
(e.g. "Now I am getting the error: An error occurred saving your data to the server. Please try again.")
Poor browser support.

Beta testers test our apps for free. It would be nice if when the app/game is published in the marketplace we could include a list of the testers that helped us so they can get the app from free instead of having to buy it.

As a recent purchaser of a Windows Phone: I love the platform, and it has huge potential to grow in competition with Android and Apple. I am concerned however that Microsoft are not pushing enough for access to successful top selling apps, which are popular on the Iphone and Android platforms e.g. Instagram. If Windows Phones are to compete they have to acknowledge the big selling apps, or they risk losing market share rather than gaining it.