Albion is part of the new type of gamplay servers. I've only been to a fortress on beta server (old school gameplay). The ones on beta contain many many groups of cataphacts and horse archers. whether or not this is the case with the new gameplay servers, I do not know. Maybe it would be simple to figure out if you send a single troop there to see what type of troops kill him. this can only disprove what I just say, but it does not prove that I'm correct in the assumption.

Nothing in the near future... I think those are the hardest groups the developers have ever made. and there is not just one of those groups, the fortress boasts the most groups that I think the developers have ever allowed to spawn (I think its around 22 to 25 groups). Besides, the fortress is not a historical/town, it does not produce troops and the population provided does not support troops.