I know this kind of idea probably exists already in these forums. This is really just something I really would enjoy thst would probably keep me playing for years and wonder if others would love if SE implemented it. After you hit 50, get the gear, beat the primals and explore everything, what would keep you playing ARR? For many, including myself I love character progression and diversity to games. Inbetween pve content I think it would be amazing to have a war filled, giant, snd beatifully created map for the sole purpose of massive pvp styled capture the castle fights, or RvR. In this map would exist 3 main forts each with their respective crystal. 1 red, 1 blue and 1 green. Players from corrisponding servers would compete to see who can capture the enemy bases and hold it for the longest period of time. In this map, there would exist Bahamut Zero which would act as a world boss that spawns for the team that can hold the 3 forts for 20 minutes. But here's the catch, you have to kill him while other server enemies are still trying to kill you, you fight two battles in this moment. After defeating bahamut each participating member would recieve extra SP or server points which would act as currency for special RvR gear. And 5 lucky participants would drop bahamut custom gear. These SP points would be acquired by defeating other enemy players as well.
There would exist a leaderboard for each class for most accumilated SP points to show who reigns supreme in the RvR arena. This would give many players inbetween pve content to strive for and enjoy RvR. In this massive map there would exist 2 save/spawn points as well as 1 bridge per server side. The bridges would all connect to the center which would host hunts, as well as open field skirmishes and duels. Anything can happen. This endless accumilation of SP which would be traded for special gifts will give players a more dynamic and different way to continue character progression inbetween pve content. I would love to war against my fellow FF players from each server while playing some pve.
Each player name from each server would be displayed as this connects the community better. Fighting against 'fresh meats' would be dull as you wouldn't learn and appreciate your enemies as much. These kinds of ideas I hope follow through in FrontLines, I would be in love with the game, if managed properly. And hardcore pve enthusiests wouldn't lose anything by such an expansion, only something else availsbe to do in the world of FF.