The single most important thing that needs to be done is to bring in GvG. That is what Guild Wars is all about and the reason why GW1 pvp was unparalled (that plus HA, RA and TA).
The format of the GvG should revolve around a guild lord in each base – (I read earlier an idea that guilds can be given a small degree of choice to customise their base defences – i think this is a great idea and adds another layer of strategy to GvG’s) with teams of possibly 8 v 8 or 10 v 10 fighting to defeat the enemy guild lord.
The maps can have additional strategic elements to them that would offer advantages in the fight such as capturing an outpost of some kind to give a damage or health bonus etc. The Guild Lord should be very difficult to kill, with NPC’s surrounding it and possibly bodyguards who heal the lord also – Games should last a maximum of say 24 minutes with the tiebreaker of who does the most damage to the enemy lord being used (just like GW1)
Also, you need monthly tournaments just like GW1. This creates excitement as every month guilds practice up to the tournament and given that it is only once a month, there is a real sense of satisfaction if your guild does well. Just like GW1 I would suggest daily tournaments to get Qualifier Points to qualify for the monthly tournament.
The rewards for performing well in these monthly tournaments should also be tangible and players should be able to “show off” that their guild won the monthly tournament. Possibly some kind of aura around players who placed in the top 16 of the tournament, the winners being gold, top 8 being silver etc…
I believe this kind of game modes and tournaments will bring the longevity currently lacking from capture point play, and as a result bring many pvp players back to the game.