After a few more FfH games I have a few more suggestions and would like to see what everyone else thought about them.
I think Assasins are understandably strong on the attack but should be weaker when defending against melee units. IMO the assasins are too powerful on the defense. A 100% against melee units is understandable, but an assasins strength lies in the ability to suprise attack opponents undetected until its too late, meriting the large bonus. However, I think that they should have a -30%? bonus which comes into play when being attacked by melee units. This keeps them strong against melee units, but means they are stronger when attacking than when they are defending, which is what I would expect of a "real life" Assasin.
I also think that the Baron should be immune to disease, as werewolves in general, getting disease just doesnt feel right for me. However, to try and balance it out, why not make it so that only werewolves personally "sired" by the Baron would be immune also. Giving the werewolves in the Barons lineage a better significance than those werewolves created by his offspring. Even if it is not Immunity to Disease, I think there should be a bonus for werewolves personally created by the Baron.
Also on the werewolve topic, have you considered giving the Ravenous Werewolves the beserk promotion? Seems fitting that a newly created deranged ravenous werewolf could also be described as being beserk, with an attack bonus and a reduction in defence. This fits with my image of a ravenous werewolf on the rampage, more comfortable attacking everything in sight than employing cautious defensive tactics. To balance it out a bit their strength could be reduced to 4?
The basis for these points mainly comes from a few turns in my current game. I am currently playing with the Ashen Veil and noticed that their units dont have any cure disease ability, well I think they should have maybe one unit that has this ability because, as someone mentioned in an earlier post, its a pain in the behind having Rosier the Fallen catch disease, fair doo's they are the bad guys though. I also had the Baron catch it, as one werewolf attacked a city stack which had disease, when it was successful, the newly created Ravenous Werewolf also had disease and, as it is spawned in the tile that its creator attacked from, it infected everyone in that tile, including the Baron! Quite infurating!