Now what about Outland? If you were to update Outland, what would you do?
First and foremost, I'd replace all of the Azeroth beasts with alien versions. Azeroth crocs, wolves, owls and raptors etc should not be on Outland

I'd certainly advance the story along, plus intro a couple of new player races, with a small number of new zones added to the mix. A few all new zones, some northwest of Zanga/Blades Edge, and some south of Nagrand. For the Horde, Ogres would start in the Vortex Pinnacle, no longer listed as a Blade's Edge Mountains subzone, it would now be a zone of it's own. The Alliance, Arrakoa would start in... someplace. As the Horde/Alliance war continues, it has also reignited on Outland as the factions struggle to control what resources exist on the shattered realm, as well as clean up the broken and unorganized demon forces that still remain.
I'd make better use of the floating islands that exist on the edges of some zones, and above Nagrand. Little outposts/towns, could be added. At the very least, some bird mobs. Perhaps a few of the edges of a zone could be strung together with bridges and form a settlement or a port of sorts.
Speaking of ports, Shattrath would be given a makeover. The rebuilding of the city has gotten well underway. Less slummy in the lower city, and both Aldor and Scryer factions have moved on or out of their tiers, which are intergrated into the city better than they currently are, and redesigned as Horde and Alliance standpoints for all rather than individual race factions. Included in the Shatt make over is a flight tower, where the flightmaster resides, and where rather than a zeppelin service, the goblins have at last finished their Rocket from Area 52.
One rocket would take the player to a Neutral/Sanctuary Naaru establishment in the new zones south of Nagrand. These zones are under threat of a still powerful force of Burning Legion. These demons used powerful fel energies to resurrect a long dead Gronn. The plan backfired and this mighty Fel Gronn quickly enslaved the Legion forces.
The other rocket would take you to the northwestern new zones, where other threatening but non Legion stuff would be occurring.
Ok, enough of my ramblings. I have plenty of other changes in mind to the existing zones, but I've talked enough for now

Someone else have a go, I'd love to hear other peoples ideas