In order-
1. I like that this game doesn't have missions/quests that are simply a bunch of grinding. Maplestory almost only had grinding quests, and this is why I quit playing Maplestory. I would, however, like to see other types of missions/quests. Something as simple as "Complete a Tier 2 run!" (which is kind of grindy, but at least it's more variety and you could pick which gate you want and whatnot). Maybe they could make it a mist tank upon your first completion, and then x amount of crowns/tokens/heat/whatever else (randomized) if you do it more than once. Maybe put a cap of like, 3 times a day though. Unfortunately, there aren't a whole lot of quests to be had in terms of variety in most MMOs. Even WoW had (has?) some pretty grindy quests. The only other quests that wouldn't be terribly grindy would be to defeat the bosses. But we're already rewarded for doing that with tokens.
2. This sounds like an amazing idea. It also sounds like the arenas we have now, but with more depth. Like, danger rooms combined with arenas and a handful of absurdity. But I think it should be a crown fee (say, 10k?), as those who have all 5star gear no longer have a use for crowns, and 15 CE is probably a pittance for them, so it would only cause a huge inflation in the energy market (as much as I hate to be the one to make this thread about energy, lol). It's true though- if they can get more than 5k doing one of these rooms, then they've already profited, so to speak. As it would have cost them 15 CE, and they would've gained 85 CE from doing it (as they really have no use for crowns). Otherwise, make it open to all players. But I really like the idea of giving people who have already reached the Core something more to do than just go through the depths of the clockworks (or farm Jelly King, or farm Vanaduke).
3. I uhh...personally don't care for PvP. I read somewhere on the forum that they have every intention of bringing it back, though, and that it was supposedly only taken out to fix it/spruce it up.
I didn't play during the preview (though I think that would've been a really cool experience, and I'm so jelly of everyone who got to), but even playing from when it went live, I feel things are already a bit stale. I understand that it's a relatively new game, but it's a bit concerning when I log on, and the 38 smiling faces of my guildies that used to greet me are no longer there. Having beaten Vanaduke, I also feel like there's really nothing left for me to do in the game. Sure, I could tempt fate with Vanaduke until I can get a Fang of Vog, but in all honesty, I don't even want a Fang of Vog. I really think that to up the variety some, they should add more levels like the ones in Firestorm Citadel. I found those to be the most interesting, and the ones that required some actual strategy and (preferrably) some teamwork.