May as well have my say.
Mine are just architectural suggestions - have made these already Andrei, but to reiterate
1) If we are using POCOs and not the entity framework generated classes, then lets go code first (part of EF CTP4) and do away with the EDMX. Development should be domain driven, not database driven.
2) Implement the repository pattern, as now the business layer is tightly coupled with data access. We've gone from one extreme (bloated provider model where people could add their own database specific providers, but probably wouldn't want to) to another (simplified data access where people may want to implement their own data access layer (say L2S, NH, Subsonic or even back to classic ADO.NET and Stored Procs) but can't).
3) Implement dependency injection. Believe me, this does make development easier and makes your application more testable. If you were looking at using a different data access technology, and you had implemented the repository pattern,
and you were using DI, you could migrate each repo one by one rather than all or nothing. My preference,
StructureMap. And regarding pluggable architectures, it doesn't get much better than StructureMap's assembly scanning capabilities. Just drop in a dll containing a plugin and your application can load it and use it.
4) Testing, testing, testing. nopCommerce is becoming quite a large application and yet to this day we do not have even one unit test. Yes the community will help submit bugs
when they are found but we need to make sure that nopCommerce is tested as well as it can be before a new version is released and people start upgrading.
5) More frequent releases. Why not release new versions more frequently, especially when bugs have been found and fixed. There is nothing wrong with releasing a new minor version that just contains a couple of bug fixes and maybe a single new feature. I think people would rather have this than wait months for each release.
Okay, those are my suggestions.
It's great that the community has so many suggestions for new features but for me, these are the points that should be addressed.