What worries me is the other side of PvP - the large scale battles which pits 3 servers against each other in a seemingly never ending struggle (World vs World vs World, aka WvWvW). In the second beta weekend event, I spent some time in this mode, and recorded a short video (with an admittedly terrible framerate which may be in the single digits).
Below, I have outlined my concerns:
* Lag - obviously, when you put so many characters in one area at the same time, you will get lag. I don't think this is avoidable in any game. Even if you have the best computer in the world, if there is server side lag, you will notice. Structured PvP is, for the most part, lag free, because of how the number of players are controlled.
* Zerging - this is a term which means to overwhelm by raw numbers. I've seen it in all games with mass PvP - the side with more players wins. The thing is, many players tend to join the side with more players, making the imbalance even worse. ArenaNet intends to deal with this by switching up the servers from time to time; that is, if a particular server is overpowered/ underpowered, they will be rematched with other servers which are closer to their level.
* Durability loss - In Guild Wars 2, your equipment takes durability damage. This is normal for pve but annoying in pvp. What can happen is if you pvp too much, your equipment can break and you won't have enough money to repair. I suppose this won't be a problem as long as you play a lot of pve, but consider that pvp is endgame content. What if I hit the level cap and focus only on pvp? I will be broke and naked. I think they could have removed this from Server PvP because it takes some of the fun out of it. (If you look at around 4:15 in the above video, you will notice that I respawned with broken armor)
* Range > Melee - I remember having a discussion with one of my friends about large scale PvP a year or 2 ago. I kept saying that ranged classes will always have the advantage in this mode, while he was convinced that ArenaNet could make it balanced.
The nice thing about GW2 is that classes aren't restricted to one type of weapon. So you might find a Guardian, the tank class, using a staff. This gives classes some flexibility. However, ranged classes will be better at ranged skills than one who was built for melee. Also, ranged builds will always be better when facing a large group of enemies. Why is this? It's simple really - if you run ahead of your allies to melee your enemies, you will get focus fired down before even swinging your blade.
*Server population - This type of PvP is obviously heavily dependent on the number of players on the servers. GW2 may be very popular, but let's face it, the population will decline after a couple months. With so many servers, the dedicated gaming community will be diluted, reducing the impact of these large scale battles. I tried taking a supply camp together with another player in the beta, but the bots were too much to handle. Maybe we were under geared, but it just goes to show that if you can't muster a fairly large attack force, there's no way you will ever take a keep or another valuable capture point.
* Eternal war - ArenaNet boasts that these battles go on forever, so that you can jump in anytime and participate. This sounds really great and during the first month or so I think it will be; but as the population dwindles, you might find yourself alone in this huge battlefield. Actually, I joined a few games in the beta and was a bit lost as to where the battles were taking place. I suppose the best way to organize battles will be via guilds, which is kinda the point of the game.
But still, compare this to other games that have mass PvP at scheduled times. All the gamers on the servers know when everybody will be engaged in the wars. That way you can be sure that a decent amount of players will turn up.
* Large maps; no mounts - The PvP battlegrounds are pretty large but Guild Wars 2 has no mounts and no intention to implement them. Instead they have waypoints to which you can teleport for a small fee. But in order to activate a waypoint, you need to control resources and certain capture points. This puts a losing team at an even further disadvantage.
I was thinking that mounts could be implemented in WvWvW PvP alone, just to allow slightly faster travel from your spawn point to the battle. They would be unusable in battle and the rider will suffer falling injury if hit while mounted. It's very unlikely that ArenaNet will implement mounts though. That's too bad, since I like mounts, especially when they can signify achieving a certain milestone or accomplishment.
To conclude, I really like Guild Wars 2, and I hope that WvWvW remains exciting as long as the servers remain active. I'll be playing as soon as the servers open in August!
*Puts on flame resistant suit*