CS jav cav was op in A25. But now they are not as OP because of the acceleration mechanic and the buffed spear cav hard countering them.
And speed is exactly why we make cavalry in the first place
This is a good idea in my opinion
"QUICK! Nerf the champion spear cavalry!"
Meanwhile, CS javelin cavalry: Exists
The main reason ALL cavalry is OP is speed. They're simply too fast when compared to spear infantry (which should be their counter).
Either increase hoplite armor, or decrease the cavalry speed.