I really like this mod for its great ideas and because it's almost a total conversion in so many areas. However, the weak AI is really a big problem at the moment.
I've abandoned all of the few games I've tried so far quite early because it became clear that the AI would be no match. The biggest problem has always been to cope with the barbarians for long enough to build an army of Axes and a few Adepts, and from then on it was easy. The AI still had warriors and the like for defense, and the promoted axes leftover from the clashes with the barbarians made city raiding really easy.
In my last game Orthus was born just a few tiles north of my copper city. At first, he went for the copper before I could build Axes and Pyre Zombies, he took the city and I lost. On reload, he went for the other city so I had time to build a force. I abandoned the city, let him march in and then killed him with a few Zombies and Axes. The Axeman who finished him off instantly got to Combat V and took his weapon.
A few turns later I took my force of about 5 Axes and 2 Zombies and easily rolled over three cities of one of my opponents to the north. He only had Warriors for defense -- it was ridiculous. I had already build three or so Adepts and hooked up two mana nodes. I then abandoned the game because apparently there was no challenge.
This was on Monarch difficulty, and the biggest issue were the barbarians in the first 100 years. On higher difficulties I found the barbarians too nasty to deal with, so I'm not ready to play on ridiculous levels just so that the AI can compete somehow.
A lot of work has to go to the AI, and then this mod will rock on single player. I'm recognizing that it is not easy to make a good AI -- Blake, who's doing the improved AI for Vanilla and Warlords seems to be an exceptionally talented person, and still it seems a long way to go there to create a competitive AI. FFH is quite different from Warlords, so I guess the work needed here will be substantial as well.
Probably it would be a good idea to fork off Blake's AI at this point before adding more features to the mod.
In my eyes the weakest points of the AI are overexpanding while neglecting military technology. Maybe there are also design issues not directly related to AI performance. The designers of the original game had their reasons for allowing a cheap, early city defender (Archer) which you can only overcome by employing good tactics and using your opportunities well (read: hook up copper early and axe rush).
The über-promotions possible in FFH throw this concept way off balance: attackers can be promoted more easily by picking fights, while you rely on enemy aggression to promote defenders. You collect your level 3 troops that are left over from barb fights and then pick any opponent to conquer -- that is too easy for any seasoned Civ player.
Also, the early strong barbarians plus Orthus and the Skeleton Ship add a tremendous amount of luck to the early game. I think barb strength should match the average strength of the civs, like in Vanilla.
Still, I'm looking forward to any improvements to come and I'll be happy to play a lot of FFH when it's ripe ;-).
--Sigi