I much prefer Viconia as a person and as a Cleric, but Anomen does a good job of killing things with Holy Smite (My favorite Cleric spell early on in the game). Really, it comes down more to a RP perspective than powergaming imo, they are both pretty good at what they do.
About the Fallen Archer... I doubt the Archer CAN fall, given that he is using the Generic Archer (i.e. fighter) kit (as opposed to the Ranger Kit). This means he doesn't get stuff like Racial Enemy (I think) but it also means that he should be immune to becoming Fallen.
I may be wrong though... Never been an Evil Generic Archer as far as I can remember.
Korgan would be a great addition to your party - The Dwarf has a fun personality and is the best Fighter in SoA (Well, PC could be superior if you wanted to be). Nonetheless, he's an amazing Tank and with certain HLA and an upgraded Axe from ToB, he can still kill things amazingly well later on.
Plus he owns Demiliches with his Enrage (or Berserk, I always forget which it's called
)