PvP and PvE class.
Warrior
Currently playing Heart of Thorns.
Being Legitimate here:
Guardian: A support/Tank class good for both! (excels in wvw)
Elementalist: Excels in wvw where it’s aoe’s are useful but still rather good in PvE and PvP
Ranger: The master of PvE with having it’s own 20-40khp tank while it pelts bullets into the enemy, but with it’s recent buff it is viable in PvP.
Engineer: Really good at PvE and meh at PvP
Warrior: Reasonably good at both
Necro: With all of its summons it is good in PvE but with power/wells it is good for PvP and WvW
Mesmer: Very good at PvP, not so in PvE
Thief: Great at PvP, not so good in PvE
Being Legitimate here:
Guardian: A support/Tank class good for both! (excels in wvw)
Elementalist: Excels in wvw where it’s aoe’s are useful but still rather good in PvE and PvP
Ranger: The master of PvE with having it’s own 20-40khp tank while it pelts bullets into the enemy, but with it’s recent buff it is viable in PvP.
Engineer: Really good at PvE and meh at PvP
Warrior: Reasonably good at both
Necro: With all of its summons it is good in PvE but with power/wells it is good for PvP and WvW
Mesmer: Very good at PvP, not so in PvE
Thief: Great at PvP, not so good in PvE
Hmmm….
Going to have to disagree with some of your assessments there.
Engineer meh at PvP? Right now celestial Engineers and celestial Elementalists are God-mode in PvP. It’s true that now that Rangers have a 100-blades skill at 1200 range that both those professions might be feeling a bit of the hurt but then again so is everyone else.
And as for Guardian, while I agree they are wonderful for PvE game play, they really only have two choices for PvP. They can either go meditations and hope people don’t sidestep or kite their burst or they can go support bunker and give up the ability to kill anyone else without the wildest stroke of luck. There are better professions for PvP who can spec to be a bunker while at the same time still be a threat to the enemy players. (see celestial Engineer and Elementalist above for examples)
I understand where the OP is coming from though. My main (and really only character) is a Guardian and I thought about just making another character for PvP, but in the end I really only want one character to play for PvE and PvP. So after I complete some achievements on him that I need to be level 80 for, I will delete him and create a new character so I can have just one to play for both modes.
The best advice I can give the OP is to do some research on the forums and maybe even ask people in-game for some advice. Then make one of each profession that they are interested in and take them to the Heart of the Mists where they will be level 80 and they can see just what each profession can do.
Believe me, it does suck to invest almost two years into a character only to realize that you are never going to be able to break out of the severely limited options that ArenaNet have setup for your profession in PvP. I do wish you good luck in your searches. 
Thanks.
“You can get more results with a kind word and a big stick,
than you can with merely a kind word.”
I agree with most Ghostly Demise.5786 saied. I just cant get around on thief. I think this class makes THE highest dmg in pve. Also I play mesmer and against thief in wvw i’m dead meat., ofcourse its diferent if you go with zerk groups, but I just tought you wanna know that. Map completion in WvW is imho easyest with thief and his op stealth/power build.
Oh and Michaeas Magister.1589, guardians and warriors are one of toughest enemies in PvP for me and I play mesmer since beta. That beeing saied, from my experience guardians and warriors can be godlike in PvP…especially warriors, but maybe thats just because i didnt encounter as much guardians as i did warriors.
But then again even if some classes MIGHT have some upperhand in pvp, it won’t necessary make you good. Godlike warriors and guardians I met did indeed have skills and a lot of knowledge of their class.
Novataris.6571, please consider playing the class and race you love the most, because all classes have potential to be good. Don’t look at who would win 1 on 1, because this game in not ment to be played like that. Besides if you wan’t to take your character to the top, it would suck if you decided half way that you hate your class =/
Hope this helps you.
If you wish you can add me and ill hep you. I play on gandara.
I can’t say what ’best" is really, but I can tell you what I liked.
PvE Thief :Maneuverable , moderately Crunchy. Fun to watch and can usually run away when needed.
PvP: I have maybe 5 minutes in PvP so no real answer for you
WvWvW: Hands down most fun I’ve had was with my Engineer. Though my Mesmer was a close second. Mesmers are often sought after to help move Zergs along that are bringing some Golems to play with. Also they are good at Dolyak escorts, which are an important mission for any team hoping to hold a map. My Engineer Is a turret spec which is annoying for other people, but handy in small groups. Heck even in big groups dropping a supply bundle can make a difference. Other folks like Flame throwers which are also nice for cleaning up the riff raff.
? Marcus Aurelius Antoninus
Really, it depends on what works for you. Some classes I don’t play because their mechanics don’t work my instincts. Figuring out how you like playing and what class works well with your preferences will make you more effective regardless of the current meta.
Really, it depends on what works for you. Some classes I don’t play because their mechanics don’t work my instincts. Figuring out how you like playing and what class works well with your preferences will make you more effective regardless of the current meta.
This, if you have no fun playing your class, you automatically care less and perform worse.
Pick what you like. All classes are viable in PvE anyway, and for PvP I am sure you’ll find a build that suits you and leads you to success.
You see. I always play the Tank class in MMOs. I tried guardian and warrior the day I started. I preferd the warrios sword and board skills over the guardians and loved how he had more HP. I quickly deleted my lvl 12 guardian and my main character was chosen.
Little did I know tank builds would be no good or how GW2 functions in general back then. Now I main a GS/Hammer warrior. I love it!