Interesting...
I only wanted longer range for the slingers because that is what they had compared to archers, if it is unbalancing then it definately needs to go. But troops with no armour and no shields should of course be sitting ducks for ranged troops, so I think it is fair enough.

AP forthe elite slingers is something I fully support, they were after all considered better at getting at armoured enemies [than archers], while perhaps not as deadly against normal troops.

I can accept the low cost for the Scythian HA, but rather than the Persian cav, which is an elite, shouldn't it be the eastern horse archers? Those were the troops used after all.

What about the basecost and upkeep of arcehrs compared to javelineers? I made the argument that archers are more expensive in general than javelineers in upkeep.

The mounted javelineers should indeed have a shorter range (unfortunately we have to consider them stading still), they wouldn't be able to use their entire body to weigh in into the throw, only the upper body. Naturally it would give a shorter throw.

Elite archers... Those with long ranges before? I don't consider the Archer Auxilia to be elite, and they should perhaps only get the range but an equally weak attack as normal archers.
Personally I would make Cretans the best archers, mostly because I have always liked them, but also because they are rather weak fighters, unlike the Chosens, Pharaohs and Foresters. Those three should somehow be hampered, just like the Jannisary Infantry didn't have Longbows in MTW. I don't mind good archers being able to fight good too, but they shouldn't be able to outshoot every other good arcehr out there. Besides, Cretans are mercs, thus available to all and none at the same time. Much more fair. So an attack for them around the 8-9 range would be good (making certain that even normal javelins are more deadly in 1v1 with an arrow), the others stepping downwards from there.
Good archers should be good, just not the ancient machineguns we see now.