Personally, I think PvP has the best rewards currently... Exclusive rewards and bragging rights seem far more enticing to me, than some item level-who-cares weapon that'll be redundant in a few patches... I enjoy stuff like Palace of the Dead for its content, not its rewards... PvE rewards have long since become fairly irrelevant to me... That's not to say PvP rewards are fine... Wolf Marks are anything but, they're incredibly dull... SE could remove them from the game and I wouldn't notice, there is definitely a problem there IMO, but Feasts rewards specifically are fine, for the most part. The fact that Season 2 is actually reasonably active at all (despite zero new rewards) is evidence enough of that...
Where I think PvP really suffers in this game is the developers... They've got no clue what they're doing, they've got a "Throw shit at the wall, and see what sticks" approach to new PvP content... There is no structure here and no longevity in any of the content... Feast might break that cycle, but 4.0 might also render it completely irrelevant, and it's a competitive mode anyway... There is no solid foundation for non-competitive PvP in this game, the best we've got is Frontlines, which is terrible... Is it any wonder the PvP community is so small and unskilled? There is no where to practice without getting your head chewed off, and the developers show a complete disregard for the content itself... It's generally just off putting for new and old players alike...
They really need to focus on Wolves Den IMO, I don't think there is really a place for Frontlines in this game... Not if they're going to refuse to fix the damn thing at least... Why they wasted time on Shatter I don't know, though there are somethings that they just can't fix with Frontlines... It's a three sided cluster f*ck that takes too long to get into and goes on for too long, and is ultimately just a complete waste of development resources; Borderland Ruins and Seal Rock are collecting dust, Fields of Glory is certainly going to follow regardless of whether they add some new worthless mode to Frontlines... People get bored with the lack of variety, either you make them all relevant before of working on a new map, or you perpetuate this stupid cycle... Since I don't trust SE to fix any issues with Frontlines, I'm just going to ask that they stop developing it completely... Put that effort into new Wolves Den maps and modes, give us a Wolves Den Roulette, make that XIVs front-and-center PvP option, because filling a 4v4 match is so much easier than filling a Frontlines match... Wolves Den matches are quicker, more rewarding, more educational... Any fun I had in Frontlines, I'm almost certain can be better replicated in Wolves Den, and I'd be able to enjoy it more frequently...
I would say most successful PvP based games work by; Giving players a variety of similar game modes to play. Adding new maps to add variety to those game modes. Then adding a competitive mode on top of that... What SE has done is just a mess... Wolves Den and Frontlines are vastly different, and we have zero variety... Frontlines itself could have had variety, Secure/Slaughter/Seize/Shatter are all game modes, Borderland Ruins/Seal Rock/Fields of Glory are all unique maps, they could have had twelve combinations there... Instead we have one; Fields of Glory (Shatter). That's one way they could fairly easily improve Frontlines IMO, but it doesn't really matter... The issue here is with the competitive mode, and Frontlines is far too different from Wolves Den to really matter for that... They've effectively made two entirely different games and now we're stuck with the majority sucking or not being interested in the relevant one because they spent years focusing on Frontlines...
They really should either have never bothered with Wolves Den, or never bothered with Frontlines IMO... I'd rather have had one thing done well, than two things done poorly... Feasts a lot better than it has any right being, but the community had zero build up, we went from Seize to Feast... It's no wonder things are so terrible...