It is a problem, that is for sure.
I think tabs instead of more slots.
I’d like an account-wide or at least a server-wide shared reagent tab.
The deal is that we keep needing to go back to past expansions, like making pots for the mage tower. Leveling an engineer sends you back to WotLK for a ton of mats that are needed to be a current engineer (jeeves and moll-e).