First off, I find your ‘download’ page to be quite the mess. I’d advise you to consider a redesign, with the following examples in mind:
Blender
TrueVision3D
Ogre3D
Panda3D
RealityFactory
There are without doubt better examples out there (well, personally I find Blender’s design to be top notch quality) but these had some significant relevance to the genre one can find jME in.
Secondly, I think the ‘download’ page could also be host for various useful contributions made in the User Code section of this forum. Among these would be the Shadow Mapping and the MD5 Reader(s). A lot of these user-contributions are of such great help to so many people that I think they deserve their own lil’ category among jME’s downloads.
Correction: That is, if they are not eventually made part of jME, in which case a seperate download would be useless.
The ‘affiliates’, ‘partner projects’, ‘tools repository’ or whatever you’d like to call it, would be a simple database keeping track of the most actual and prominent side-projects to-date such as MonkeyWorld3D, Scene Monitor (1.0) and maybe also game projects, though these should at least have a playable demo out already that’s worth showing.
I think it really depends on the audience, yes jME's download page does not have different Os downloads and a fancy windows installer, but hey it's java we don't need all the categories and sub categories as long a you have a vm…
jME isn't trying to run the same gimmick as for example Torque, where if you pay a 100 buck's you get a fancy red button saying "Make my game". jME is a scene graph for people that know what they are doing or want to experiment/learn at the cost of time.
I think the download page has just what it needs, it could be better (tools/user code links), but honestly I would rather have the main contributors use there valuable time working on jME! rather than maintaining a web site and making jME look nice from the outside.
But hey it's open source. I'm sure if you sat down and used half a day compiling useful information and redesigned the download page and posted it, every one would look through it, comment, suggest and if it was better it would be used instead of the current. Let's see an example 
What I'm trying to get across is, I think it's better to say "I think this [product] is better than the current , can you use it? what needs changing?" instead of saying "I don't like that [product], I think you should change it".
Take initiative and try to improve jME.
2 cent