Don't know if you're still working on the server recently, but what do you think about Guild RAIDS? Eventhough i prefer wars more than pve, Guild RAID would be a pretty cool feature in my opinion, and im almost sure it's possible. I mean, there's a similar thing in sro already, the fortress instance. It's capable to accommodate like 28 ppl (I do not know by heart).Honestly i don't know how you build up a server, i don't know shit about developing, editing & stuff like that, but you just have to make it enable for every guildmaster to generate their own instance (from the guild manager npc's for example) with edited various kind of mobs, uniques inside or even the whole map changed, maybe that dw cave map wouldn't be too interesting for most of the players(including me *cough*). This is just another way to make players play together, so maybe even some of those lonely wolves would gang up in guilds and do something more groupbased than solo fgw runs. If you ask me it's worth a try, people would like it.
At last but not least party merging would fit with this feature.
If you are still in the mood to add new features, please consider this one.
Thanks in advance.(can't wait for the server!)