I agree.
Certainly plugins, customizations and applications can be combined. Maybe prefix each entry with [plugin], [customization] or [application] or simply have separate sub forums for plugins, applications etc.
I would arrange forums categories from the top,
1) Company
2) Support
3) Version 5 Development <--- rename it "unRAID Development"
4) Server Building
5) unRAID Marketplace
6) Older Releases renamed from Version 4.X Support
7) Off Topic
Just my 2.5 cents.
Kryspy