First, I would like to say that I'm making this suggestion from a place of ignorance:
- I don't know how hard these things are to run
- I don't know what sort of toll it places in the server or dms
- And I don't know if there are other variables that further the difficulty of these sorts of events
- I have only been in server for a few weeks, so maybe they happen more often then I think
All that aside:
I think it would be great to see more large scale invasions on the surrounding gates/areas. I've always thought these invasions were fun to take part in and helped contribute to the flow of questing (i.e people die, lose their level, and need to spend time doing more mid-range or lower questing.).