Last night my good friend Kristen and I managed to discover what I find most enjoyable about Aion. It isn’t the graphical detail or the simplistic class system or the flight. It isn’t the marked progression of gear and a very active economy system, either. Hell, it isn’t even leveling.
No, the thing that I enjoy most about Aion is rifting. For those that don’t know, rifting is a form of encouraging incidental, skirmish-based pvp in the normal areas of the game. Aion is divided into two sections with a pvp section in the middle. The two sections each belong to one of the two factions. Normally you can’t go to your opposing faction’s areas – until a rift appears which will take you there. From there, you’re in hostile territory and just about anything goes.
As I’ve written before, Aion is a game that has a “safe” mirror-sheen polish to very tried and true elements – classes, quests, and yes, even the soul-crushing expected grind – are all things that Aion does well to at least a fairly solid degree. This definitely explains some of its popularity since its release. Rifting, and the pvp that comes with it, is one of Aion‘s few innovations, and it’s great for a variety of reasons.
One is the dynamic factor. Sure, you could go to the Abyss, where you actually expect to pvp, but nothing beats a chance encounter in a zone where you don’t expect it. While there’s an occasional zerg, most encounters are small-scale and happen at random. The dynamic of finding targets to kill, or hunting down rifters, breaks up the monotony of “kill things, turn in quest, repeat”.
The other is the thrill. Not being welcome in a zone where you are clearly surrounded and outnumbered means you have to use different tactics to survive. Just ganking everything in sight will end your trip prematurely. No, the tactics involve sneaking around, moving quickly after a kill, and wandering in a manner that seems random, among other things. This, combined with the need to look over your shoulder, creates a potentially exciting experience that could end in 20 minutes or 2 hours.
Surfing the rift is definitely fun. I recommend it to those of you who are having a hard time keeping your eyes open after killing 20,000 mobs.

With rifting, it's all about picking your battles and using half of a brain. Changing your directions often, not killing everything in sight, staying together, and skirting zones– using all of these tactics helped us stay alive in enemy territory until bedtime.
And for all the reasons you mention, is why I don't like it. Killing 20,000 mobs to get there isn't fun.