Seemed to me that exploration xp was pretty good. I was determined to find a racial crafting book before the end of the last beta. So I made it a point to search out every single hovel, hut, shack, shanty, building, office. treasure chest, tomb etc I could find just to pillage the containers. (I learned quickly that the good stuff is in dressers, desks, and cabinets) But by doing that, I discovered so many other cool things. Like skill books. it seemed as though about 1 out of every 20 or so books that you find and read actually offer skill points in random catagories. I also found lots of Provisioning recipes, gathered tons of crafting materials, and found myself getting hooked on both exploration and crafting at the same time. But I was steadily gaining levels all the while.
So every time I would see a quest npc, I would say ok, i'll get back to him later.... but never did because I was soo hooked on exploration.
In the end I still gained a few levels while doing hardly any quests, got every skyshard, maxed out Blacksmithing..... and YES finally found a High Elf crafting book in a dresser. I was soo excited to finally find one. it felt rewarding.. Then of course I had to rush back to a forge and make my Orc a full set of High Elf Plate mail lol.
So in a nutshell, got some good xp and had tons of fun while not questing very much at all.