Its actually woth it because in wintertusk you get thousands of ex and you level up pretty fast. I entered Wintertusk when i was level 49 and about 15-20 minutes later BAM! im level 54. I was pretty angry about the amounts of ex in grizzleheim but it is SOO worth doing to go to wintertusk.
about is how little EX you get I mean compared to krokatopaia you get none pretty much and the quests are really hard