I'm sorry, but I disagree. Just because two civilizations are calvary-based doesn't mean that they're bastards as you said.Most of the nerfs are too bad, but the new civs are just utter crap, there like bastards of the old one i.e. hun - magars, celts - slavs, byz- italians, pers + turks + sara - indians, incas however are different
Huns and Magyars are calvary-civilization, but they have lots of differences. Magyars has non-calvary units that Huns don't have (Champion, Arbalest and Onager). Magyars' Hussars are cheap while Huns' Calvary Archer are cheap instead. Magyars have the Maygar Huszar as unic unit, which is worth producing after researching Mercenaries. Huns, however, rarely will make Tarkans because they cost gold and aren't that useful.
Celts and Slavs have a similar tech tree, but Celts' siege is more powerful because of Furor Celtica. It's also interesting to point out that Slavs' Monk can have extra armor with their unic technollogy, so there are more chances to see Slavs using Monks thant Celts. I just don't get why Slaves are classified as Infantary and Siege as their unic unit is a calvary unit and as siege as the workshop just works 15% faster (Mongols' siege moves 50% faster and they aren't Calvary Archer and Siege because of that).
The link of Persians, Turks and Saracens with Inidians I didn't get. You could point it out, please. By looking Indians teech tree I found them very different from Persians, Turks and Saracens. Indians don't have Knight (the only civilization without Knights), so what you use to rush in Castle? Camels? Well, they lack Knight, but they're the only civilization that can research Imperial Camel. That makes Indians very different.
Byzantines and Italians? Italians don't have Siege Ram, Squires, Camel and Palladin. Italians got bonuses for water maps, Byzantines don't.