Warhammer offers up a total of 15 scenarios that are limited by levels
DateTime:7/8/2009 5:21:12 PM

While some are more interesting than others, they are all set on a timer so that a single battle will never last longer than 15 minutes.  This means that even when you end up with a group of complete idiots you only have to endure it for 15 minutes and then you exit and collect your points and can try again.  This alone gives Warhammer the nod on scenarios.  Scenarios also give you actual experience and build up a level system that gets you more rewards.  In Warhammer, it is possible to play the entire game and do nothing but play scenario after scenario.  Without question, this is the most fun part of this game.

If you love to play battlegrounds and scenarios, and have been playing WoW for a long time now, you will probably want to stick with Warhammer simply for the novelty.  The scenarios are still fresh, new and interesting, with the strategies still evolving amongst the players.  Coming back to Lich King just means playing the same battlegrounds you are already sick of, with just one new addition.  In a couple months when you start getting tired of the Warhammer scenarios, maybe the old WoW ones will look like fun to you again.

Warhammer Scenarios and WoW battlegrounds are essentially the same thing.  You teleport into an instance, hook up with a number of other players and play a mini game against the other side.  In addition to the four existing Battlegrounds, Lich King adds Strand of the Ancients.  In this battleground you alternately attack and defend a keep using siege weapons to batter down various gates to try to get to the top.