I am a R27 Engineer festering in the Badlands. Here's what's usedful for the class IMHO:

ActionBarColor - turns abilities red when target is out of range. Nice for grenades both with and without throwing arm tactic.

Killing Blow - every now and then a blind squirrel gets the nut and an engineer gets a death blow. Really nice for cherishing these moments. Made me start watching Destro health bars a lot closer and switch to rifles to finish them!

Warhammer Scrolling Combat Text - really nice to be able to see what abilties enemy is using to take you down so quickly (all of them). 

 Also try AnywhereTrainer and RvrStats to have more of a "WOW-like" character window with talents and PVP stats without going to a trainer or the Tome. 

All these seem to working after the 1.6 patch today as well.  

 

i did some calculations from xfire and was not far off from this. we know there are over 11-million WOW users. there are around 100,000 xfire users playing wow per day for a ratio of .9%. If there is a similar ratio for warhammer which has 3500 xfire users playing per day then the number would be around 380,000. i figured this was artificially high since so many wow players are in asia and not likely to be on xfire. so i would estimate around 250,000 active players. i personally let my subscription run out in early jan after the 3 months were up. what's interesting about this estimate is that LOTRO may have comparable numbers to WAR or even surpassed it recently, though turbine has always been hush, hush about subscriber numbers.