In my opinion, the SDL AppStore (formerly OpenExchange) is missing two things to really make it shine:

1. SDL should host the app installers. They should not be hosted on a third-party website. Firstly, it is more secure if SDL controls the hosting, since you never know what can happen with third-party sites. Secondly, it is a hassle for developers to have to maintain a server just to download from (though it should remain an option).

2. A built-in way to monetize apps, should you chose to do so. This could be accomplished by utilizing SDL's existing payment infrastructure along with a small SDK to include, allowing you to check licensing status easily.

Of these, item 1 is by far the most important one.