It'd be nice if pvpers could grind to fuel their pve endeavors, however your fourth option isn't going to necessarily attract the good kind of pvers. The people who do pvp do it because they enjoy the competitiveness and the rewards reaped from coming out on top.

The fact that you gain exp to your pve lvl and getting tomes has only attracted people to come into frontlines only to sit their and alt tab and watch movies or w/e simply because they get something out of it regardless of their participation or win/loss and because pvp match completion is faster than dungeons or PotD. They need to rework how kicking those people out works or adding a system where you get currency for participation rather than just sitting there since pvp match success hinges on group coordination.

With pve it's all about leveling and gearing quickly with the least amount of effort and if pvp is the way that best matches this then they are going to opt for it, which isn't necessarily a good thing.