I think it would be a cool feature to be able to purchase, with inferno and aqua (or gold)extra equipment slots. Devs would create pricing, max slots, etc. Sorry about "low effort", it's just an idea
Ideas there need to elaborate and flesh it in. Maybe use other pieces of eq we have to modify current equiped gear?
Interchangeable sounds good. But extra slots would make people such as GH and SH even more overpowered as it is