Need guidence
Guardians aren’t particularly slow, though they are defensive. The problem is if you’re just offensive and not defensive in WvW you’re going to get eaten. You need defense in WvW.
Generally speaking right now, warriors are one of the better dungeon professions, along with guardians and mesmers. In WvW however, guardians, eles and mesmers are some of the best professions.
Rangers, and engineers are generally the least liked professions over all, even though if you play them really well, they can play anywhere…but many don’t play them well.
Don’t know if this helps or not but in spite of your reservations, I’d still try guardian.
I suggest warrior as you can have a pretty good balance of offense and defence and you have a great set of ranged and melee weapons to use. I have tried almost every profession and i feel strongest with my warrior. She is nt invincible but she can hold her own in most situations and contributes a lot in dungeons and wvw.
I would suggest playing a warrior. They’re easy to pick up for new players, good in pve and also needed in dungeons. They can also hold their own in WvW.
Also recommend the Warrior.