One of the main things stopping PMC being a workable platform for Minecraft maps is the very random-seeming categories from like 2012.

Parkour maps, for example, are a huge part of Minecraft maps but don't even warrant a mention in the categories (while "water structures", whatever that means, does 💀)

I propose a complete revamp:
(Blue = Keep from old, red = remove, yellow = rename, green = add)

Challenge / Adventure
Educational
Environment / Landscaping
Pixel Art
Music
Other
- 3D Art
- Air Structure
- Complex
- Minecart
- Nether Structure
- Piston
- Underground Structure
- Water Structure
Land Structure -> Build
Redstone Device -> Redstone
+ Parkour
+ Horror
+ PVP
+ PVE
+ Puzzle
+ Escape Room
+ Minigame

This imo seems far more comprehensive. Other things you could consider: elytra, trivia, etc

Edit: Additionally, please allow users to filter by minecraft version in the same place - there's only the upload timeframe