So, there are a few civs that have civ bonuses that are missing key techs. This results in the civ being toned down. Examples:
Cumans. They are missing husbandry. IF ANY CIV deserves husbandry, its them. But, husbandry gives +10% mounted speed, and their mounted units get +15%. +25% mounted speed for a civ that gets no access to walls or bracer is apparently too OP. But why? They don’t get a fortress to retreat too, and with -1 range for their cav archers, they can’t hit and run good. If your gonna nerf the hit part, why also hitt he run part? Yes, you MIGHT not be able to catch their cavalry. And so what? Deal with it. Their buildings aren’t mobile. If you chase their cavalry off, go raid their base.
Byzantines. They get +40% building hitpoints in imperial age. But, hey they lack access to architecture and masonry. WHY? From a historical standpoint, the byzantine empire had GREAT architecture, not to mention masonry. They had some of the most impressive structures of the middle ages. Just look at constantinople. But, apparently +60% hp is TOO MUCH to deal with. Again… bad design choice.
Britons. They lack the thumb ring. The definitive tech for archers that would make longbowmen work like they did at agincourt, and they just HAD to be not get it.
Celts get wood chopping bonus, but no two man saws.
The result of these decisions is that ALL of the civs become very bland. Your civ bonuses are worthless, because you lack the tech to actually make them useful. And if you pick full tech trees you lose your civ bonus. You never get a situation where you can get the bonus and the tech to make it useful so you can have civs that break the mold. Its… sad.