For me, PVP servers are very difficult to manage over a long period of time. The longer it runs, some players will have an advantage of being on the server for so long which makes it extremely difficult for newer players to get into.
If you want my thoughts then here goes <object class="emojione" data="
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My 'ideal' would be a PVP hub leading off to two worlds (and a third which I will come back to). A "team" world and a "every man for themselves" world.
Both worlds would be pre-generated cities so gaining materials would be easy, TNT is enabled and it would be all out chaos. The worlds would have a smallish radius (1000 or so) to ensure max conflict between players as they would cross each other often.
A custom plugin for the teams world, allowing players to join groups (With a max limit) and have minimum protections, enough to cover a small base. It can be raided easily if the team is not able to care for its maintenance. Maybe some loot chests spread across the land for players to collect.
These worlds would be reset on a regular basis (Monthly or something), they would solely be for PVP and chaos.
However, this links up to the third world. The main PVP world. It is a long-standing world so no resets would happen. It could have that optional adventure roles and would generally be for factions and bases to hold up and know it would be a permanant situation if they maintain it.
Killing players from the other worlds (and the main world) would gain points, which in turn can be used to buy items or trade items between worlds (moving some good items into the temp world to gain an upper hand or move some found good items from the temporary world to your permanent world to keep before a reset)
This would appeal to all PVP types, those who want longstanding factions and adventure, or those who just want mindless pvp/destruction on something that is fine to completely obliterate.