Class slots

I am Currently creating a ruleset for my next game when ever it is. I was also revisiting the game Backpack Hero developed by Jaspel. In it, you play as a mouse with a magic backpack. Inside this backpack you store items that have abilities that help you throughout the run. All your magic, healing items, armour and weapons have to fit in (at first) a 3x3 grid. I found it quite interesting but I realised I could apply this to TTRPGs. See, I don't like classes as they feel too constrained to their archetype. If my fighter wants to cast a spell then tough luck. I put this idea on the backburner until I bought the starter set for Warhammer 40k: Wrath and Glory. Now, they use a point buy system for every thing and now I present a basic prototype. The Prototype The blue item is a feature while the red is a different feature. Size not final The two classes I plan to have are Steel and Spell. Steel can move features at a moment's notice to fit a new technique. For example, S...