I decided to give a bit of insight on my Beta experience so far. Ignoring all the bugs and crashing, I have to say it's been fantastic. There's so much more to this expansion than anything WOD had to offer, and I've yet to enter a raid. A few main points I'd like to speak on:
The questing is really well done. Alot of small quests in each area of every zone, makes it pretty easy to really get rolling through the levels while still enjoying the gameplay. I feel like Azsuna is the quickest zone by far, I'll probably begin leveling there when Legion goes live. Stormheim has some amazing quests, and is well worth exploring. Highmountain is pretty cool, there were alot of phasing issues that held up the process in this zone. All in all, I'd suggest entering a zone and finishing it completrly, you can hit 110 purely from questing and some exploration.
Surumar. This is hands down the most beautiful zone they've ever done. I don't think anything comes remotely close to it. Once you get to see it, I feel like most players will appreciate it. The level 110 questing seems interesting.
Finally, world quests. I haven't had this much fun doing world content in my time playing the game. It's awesome for the initial gearing phase, and with a group of friends will be a great way to pass the time playing. Got lots of WF gear, Guildy got an 875 piece, and the World Bosses apparently give a guaranteed 850 piece. I hit 110 today and I'm 805 I lvl already. Heroic dungeons require 810, which I feel is easily doable within a couple days.