Now that 3.1 is finishing up, and you're looking for more spell ideas I started thinking about what could be interesting to see. I'm not sure if this would potentially fall into a spell, or more of an expansion of infuse, but what about some more control with infusing and hydra hex.
I really like the fact that I can infuse hydra hex and have it pulse the entire area right away. What about the ability to infuse or shape the hydra hex and leverage different spells without having to drop the spell and recast it. The spell dancing could be kind of interesting and allow starting with a Malediction in Hydra Hex attuned to Offense, and allow infuse to convert into the offensive curse into a Malediction now geared towards defense, or swapping over to CoZ or any other spell that can be woven into Hydra Hex. Ideally, the effects would overlap, but I can see that being a balancing issue, so potentially dropping the effects upon infusing to a different spell/action.