A good architecture should permit federated shops and not only a centralized one. In that way shop mantainers could join businesses and share % of revenues keeping applications on their own sites (or not). The root shop could then expose a search engine capable to search through the federation and act as a quality assurance (or validator). So, please think about an API set to expose to the world.

I would also be interested in App stores for Swing and Web apps. Giving users an easy way to either pay for or donate money to your software has to be the least interesting part of virtually every piece of software.

The OTA (Over the Air) provisioning should have more stringent requirements for manufacturers to guarantee a sufficiently user friendly install experience of MIDP applications. Some current implementations are really horrible in this respect. For example some devices require users to enter the password two times during the install and if that's not enough the phone asks the user to give an installation directory. As if the user would be interested in typing some unnecessary directory name on a small device. Further, in this example the phone asks wether to install the software on the phone or on the memory stick. After the many many dialog displays requiring stupid information the user feels completely frustrated. Software insallation is not that difficult even on desktop computers! So the OTA spec should state at least some minimum usability requirements. That would make things better for us all. If MIDP wants to conquer the world it should not rely only on manufacturers good will to create usable implementations.

I think the difficulty of deployment is the number one issue facing Java ME. The operator/manufacturer signature process complexity and the lack of a simple distribution process make this all very difficult. A central verified repository and provisioning solution that works with operators globally can turn small development shops into a reality in the Java ME world.