It seems to me a lot of people post feedback without actually opening the map. Yes, the system would actually be better described as an equipment limitation system, but that doesn't really sound nice, does it? Though you are right.
A lot of people seem to have this (logical) problem. They seem to think because the demo only has Hand, Offhand, Chest, Boots, Jewelry slots means that you cannot make your own slots with their own classifications. Let me go a bit further on this. A slot is simply a dummy item that stands there so you can hover over it for a tool-tip and see a visual of the type of item you can equip there.
In this system, the mapper can assign a number of different classifications to any slot they create. They can then also assign one classification to any item they create. An item can only be equipped if there is a free slot that has a matching classification.
This way, let's say I have three armor types: "Chainmail, Leather, Cloth". And every Hero in my game can equip one of these. Chainmail wearers can equip all, Leather can equip cloth too. So we just add classifications "chainmail" to all chainmails, and the same for the other items.
Now, we give a chainmail class a slot with all 3 classifications, a leather class a slot with only the first 2 and a cloth class only a slot with the cloth classification.
I hope this does not cause any more confusion as it seems to be a core problem that people think any slot outside the demo map does not exist.