Idk tbh it's pretty late in the game for them to implement this but I hope they bring some meaningful features.
I'd like to see the clan system tied to the proposed upcoming competitive and community PvP tournaments etc. so that in order to participate in a war on the official ladder you have to have been in the clan a certain amount of time.
If Jagex does something to discourage all the multi clanning then maybe there will be more actual clans fighting each other instead of just a few big masses/alliances. Maybe others have ideas to incentivize loyalty to your clan and disrupt the trend of toxic clan hoppers.