Aion has amazing PVE content in 4.0. Anyone who thinks different has little other MMO experience. Just think about how many different ways you can most of the 4.0 instances and still be successful (bridge, tower, hyperion, DR, etc.). I've never played another game that allows for such a huge variety of classes to perform different roles either. Just take tanks for examsple--most games have 1, maybe 2 tank archetypes. Just in doing hyperion over the years I've seen a glad, templar, gunner, sin, and aethertech (5 out of 11) be chosen and successfully used as the main tank (yes, gunner really). And of course we also know other classes such as sorc tend to tank other easier instances. Variety in class set-up, variety in the way we run things.
If you wanted a strictly pvp mmo, you picked the wrong one. To get geared in Aion, you will run a lot of PVE, so get used to it--the game was purposefully designed that way. In 1.x patches we ran upper forts (and farmed guards pve) for medals and AP, 2.x we ran Esoterrace and upper forts, 3.x we farmed keymasters in the eye and rifted to guard farm (satra treasure horde wasn't great), and in 4.x patches we run a crap load of bastion and do upper forts if we have them (at least until you get your gear). Most people, even the ones who deny it, spend more of their time in Aion doing PVE than PVP.
If you out pvp the opposing faction bad enough, you get the good PVE--which in turn allows you to gear up better for PVP. That's the cycle baby.
As someone who has raided in and pushed progression in several other triple A titles I'd rate Aion's PVE in 4.0 as amazing in variety and scope (in previous content patches it was good, but severely lacking in amount).