I cant understand why operatives/scoundrels are hard to play for you all.. Concealment just got one out of stealth rotation abd one without, lethality has to manage 2 dots and TA procs(cant say something about the healer). Both trees got about 3 defense cds.
Snipers/Slingers are hard to play when they are under pressure, but in every other situation they are just 5-6key facerollers.
Personally i find pyro-powertechs are not that easy to play, post 1.2 its really hard for me to get perfect PPA streaks
But i share the opinion that sents/maras are the hardest to play, especially combat, watching out for ataru procs for the autocrits, armorpen+cripplingthrow+masterstrike combos....(all of my impressions are pre 50)
Sorry for my bad english