Demon form weapon swap trees

Currently, Infernalist's demon form gives you a third weapon set/tree, and casting a spell using any tree other than the demon form weapon set takes you out of demon form. This means that, when in demon form, you don't get to make use of the tree swapping.
I'd like to see having trees tied to weapon sets without weapons equipped working in the form.
Considering the already heavy penalties you're building around for the skill, it really hurts that you can't make use of tree swaps. Ultimately, it just feels bad not being able to use a mechanic that is otherwise really cool. For example, having different trees for different elemental damage types can't be done.
Demon form is an archetype that would benefit the most from tree swaps (due to having all damage come from general increased spell damage %) and would feel massively improved not just in terms of strength (I'm not sure it needs a buff tbh), but also just in terms of how fun it is to play.