It's not news to anyone that SE doesn't pay much attention to pvp, but even though I'm a pvp lover, I can see some possible problems that keep people away from pvp.

I'll list it:

1- players take a long time to die
2- 3 healing potions slots is too much - have you ever heard the Brazilian saying "1 is great, 2 is good 3 is too much"? yes, 1 potion slot is more than enough (this would solve two problems)
3- the main reason for the infinite delay in pvp queues (in my opinion) is the necessity of having 4 predefined roles (1 tank, 1 ranged DPS, 1 melee and 1 healer), let people build their own groups with the classes that want, as this opens space for creativity
players in making new goals.
4- rewards that make us want to conquer them with all our strength - the biggest goal of every mmo player is to go after achievements, glamours (when mmo has this system) and mounts. I know that all of this already exists in the current pvp, but it's a small amount and they're not so cool, it doesn't make us want to conquer them that much. And that's not SE incompetence, it's just lack of interest, so...please look at the pvp players, we love you guys, love us back.

I think this is one of the problems that bothers the most in pvp, if you know of another one, let's talk about it.