Stability

[LAF1994]

Cities declaring independence is an important aspect of the mod. Needed for the current stability balance.
Would you prefer having only full collapses? I find representing instability much better with the possibility for both low scale independence declarations, and total collapses.

Barb spam is not that important from my perspective, also one could argue that it's fake difficulty in the mod.
I hope most players don't mind it though, it's an easy way to balance various UHVs, and personally I like to see some other civs represented, even if only as barbs.

Also, barbs can have 2 type of spawns, the more dangerous one enables them to spawn inside borders too (it's not that common though)
About Pecheneg raids in Hungary, here is one example: https://en.wikipedia.org/wiki/Battle_of_Kerlés
Warring with them on the eastern borders of Hungary was pretty common though, especially in the 11th century.

I agree with your Byzantine and Arab/Cordoban points, not yet sure how will I improve those situations.

The problem with city independence is that it's completely arbitrary. Also, it doesn't make sense for the garrisoned army to go over to the rebels for no reason. A better setup would be a 'revolt' event which spawns a small army to attack the city and sends it into anarchy for 2-3 turns (this should probably also apply to the minor civ revolts).
Regarding barbs, the problem is that historically most nations had various means to deal with raids. In-game, training troops to deal with raiders means sacrificing development, which is a problem given how time-constrained RFC is. One option would be to lengthen the early game (increasing tech costs to compensate) so that civs don't take 300-400 years to establish a functioning infrastructure. The other problem with barbs is that their behaviour isn't very realistic; they generally just stomp around smashing improvements until they're killed. Honestly, I'd just suggest removing the pillage ability entirely.

 

[gilgames]

You can be agreed, but if you remove pillage optoin, they woulndt mean any threat except in 1070 for Byzy.