PvP only? There are some people who do not care for PvP. It might even be a decision maker for whether they would try the game or not. Will there be something like a story to pursue or quests or anything like that?

If it is a hybrid of PvP and PvE, how will it be implemented? Arenas? Zones? Other?

To my knowledge they are going for a more standard tab-targeting type of combat flow, and making that into dedicated PvP gameplay have ime never really worked out for "standard" MMORPG games so I'm pretty sure that they are going the PvE-first route but still having a decent amount of PvP content.

Regardless of if they go with a mega-server or multi-realm/server structure then I'm sure they will have both PvE and PvP instances to choose from. If they go with a mega-server then I hope they do as DCUO did, that you change between PvE and PvP instances at will when you are at a major hub (or when you sync with party leader).

Beyond that I can see having the nowdays "standard" PvP in form of battlegrounds and/or arenas, and possibly some open PvP enforced zones on the PvE instances.