I've been working on a different kind of PvP map that integrates some of the 'KotH' features you mention along with 'siege weaponry' a'la Castle Building. While gear issues are always a major concern in PvP, the biggest challenges to this idea surround the emplacements and Castle building. I think the idea's got a toe-hold via the housing system but there's a lot of work to be done with respect to how siege weapons / castle pieces would be crafted, placed, etc. I favor a consumable system where if the castle defense is destroyed, it's gone forever and you have to craft it again. Others favor players being able to recover their destroyed machinery after some period of time (with a Platinum timer buy-through).
I'm also very interested in a PvP mode where you can only enter with a certain set of gear. This would give us a chance to balance a particular suite of gear (and I'd wanna do this for 66's only to start with) and create a PvP arena scenario where all participants are effectively 'balanced' to a neutral standard. Not sure if I can pull it off, but what I want to do is make it so that once you're in the PvP gear and you enter the Arena, you can't change your loadout; you must remain in the approved set for your class 'til the clash is done. Leave you lose, etc.
We went all-in on Spectator mode for Call of Champions and it was pretty fun. That said, I'm not sure if it's something people would use more than once in Arcane Legends - unless you're a full-time streamer or something.
Round-based PvE stuff and overall improvements to the 'Gauntlet' style of gameplay do interest me quite a bit. We're working on something (unrelated to AL) that does this exact sort of thing - 'except for the limited lives. I'll take the life limitation into consideration 'cause I think that's pretty cool too.
Neighborhoods. You probably won't believe this, but "neighborhood" zones were part of the original housing concept. I wanted players to get plots of land adjacent to each other. The server would dynamically seam them together. Active players are put next to other active players while those who have not logged in for some time are placed in another less active 'neighbor zone.' In a later revision, I went for a 'territorial control' concept wherein players could fight for a literal space on a terrain grid to place their house.
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