TL;DR up front because I’m not a jerk: Use whatever build you like in Guild Wars 2. Have fun in everything you do. Don’t play for “Efficiency” because you’ll get bored of the game and quit because it will feel like a job.
I’ve seen a lot of hate here when players attempt to use the same build in PvE, WvW, and SPvP. Normally the argument I see is the fact that you need zerkers with focus being on damage in PvE and using that in either of the other game modes will not work at all.
I’d like to put forth an example of how a player may use an SPvP or WvW build in PvE.
For this example, let’s use a brand new player that rolled an elementalist. He/she just bought the game and got to 80 about a day ago. (For some reason they are able to fully gear their character in a few hours.)
This player role-plays, and they really want to get invested in their character, so they made a build that they researched and theory-crafted in order to perfect. This build represents their roleplay idea perfectly and they are really happy with it, so they really want to use it with everything.
So, the build focuses on being a jack of all trades mostly, but he/she picked traits to focus on survivability. He/She figured that it would be easy to live in PvE with even a crappy build, so they chose to focus on an SPvP or WvW build style.
An example of a build like this: http://gw2skills.net/editor/?fFAQFAWhUM6ZW4wxBf0AhAB5tmrRBlrLXB-TxCBAB4p+zdKNiZ/BrUGYnOirUiVn5PAOgAhcBAcVJYAPIAA-e
Now, that’s a perfect build for WvW and SPvP but what about PvE? How could he/she ever hope to get a good dungeon group together without using the typical Fire Ele Zerker build?
Simple: He/She doesn’t.
You see, if you ever take a look at the LFG tool during peak hours, you will likely see MANY more dungeon groups being formed saying everyone is welcome than you will full zerker groups. So, this player will never miss out on anything simply because they chose to have a non-zerker build.
I often see the argument against this being: “But the reason you should always use full zerker builds is because you get through the dungeon faster. A 20 minute dungeon now takes 5 minutes.”
This argument falls apart once you realise that this is a new player. He/She hasn’t run through the same dungeons five hundred times like some of you have. That end goal of one gold isn’t as important to them. They still like running through dungeons. It’s not that much of a chore for them because it’s still a really fun part of the game.
The next argument that I’ve seen: “By not using a zerker build, you are hurting the rest of the people in your dungeon group by making it take longer. You might be having fun, but they probably just want the one gold reward at the end.”
This argument also falls apart when you realize that this new player isn’t joining any full zerker LFG listings. Assuming this new player strays away from zerker only listings, the other players in his/her group most likely want to enjoy the dungeon also or simply don’t mind taking longer. Due to this, the new player is harming nothing. Actually, they may be doing better than a full-zerker player would in this situation since the full zerker player would probably die a lot since the other players are probably not using a full zerkers build.
In conclusion, YES! You can use the same build in WvW, PvE, and SPvP. Assuming you are alright with taking a little longer in dungeons, enjoying the non-rush nature of non-zerk only groups, and running with zergs instead of roaming in WvW, you will do fine if you want to use the same build across all game types.
That’s the original nature of guild wars, right? Play how you want. As long as you are having fun, don’t worry about being “Efficient” enough.