Hey! I am just here to say that I am in Mirkholm Keep and in Grizzleheim andI get like NO experience! It gives like 450 or 500 at max. I fight a 1, 500 health full boss for 400 experience? No way!
Grizzlehiem is not meant to level your wizard up for a reason - you would be off balance in levels to complete other worlds. As said it does off more gold and drops to sell for gold as an instentive and remember if you do not complete this world you can not enter Wintertusk - which give mega experience and get your pet/spell quests complete.
We try to use GH as a break from normal questing and visit it in areas at a time - usually starting at level 25, so we are done with Ravenscar around level 50 or so.