OK, been playing a lot more and I'm really impressed at the depth they have.
Every time you think you have it down pat, you find another facet of the game that really throws you. For example, you can get a mount (Horses, donkeys and wagons....and that doesn't take into account the many boats in the game), but not only can you level the skills of the mounts by riding them, you can also go out and capture more horses and then breed them. Breeding can increase the tier of the horse (which allows more/different skills) and also allows faster and more durable mounts.. you can also learn skills that let you make better gear (horseshoes, saddles, etc) that affect things like speed and HP's of them.
Pretty well every part of the game I've run into so far is like this, every time you think you get a handle on it, something else opens up.
I've heard the "end game" is pretty well PvP, but so far I think I'll be happy playing just the early game (that was one of my favorite parts of Archeage too) and just supplying all the PvPers.
If anyone has any specific questions, feel free to ask and I'll have a crack at trying to answer it, but if you like "old school" MMO's (dressed up as a "next gen"), it's definitely worth a look.