Well... AFM984, usually what I would do in a situation like that is nearly ignore you (I keep an equal size cavalry unit to yours in reserve) and help out my ally with most of my army so that my team has the soldier advantage. :) If you go to help your own ally, that's when I turn back to attack when the defensive formation is broken.

If it's a 1v1, well... I'll admit it's trickier, but the strategy stays the same. Turn off fire at will and skirmish, put the Scythian Noble Women on tribe mode, then go right next to your legionary line to shoot the archers and onageers. Even a quick rush by the legionary standing a few steps away will be too slow before the noble women move away. Of course if I mess up my micro then, it's probably over for me. Having a defensive line of infantry in front of the archers doesn't save them from the noble women, unless the distance between them is very long. If so, I'll circle around with most of my army out of arrow bowshot to shoot at the "unprotected" back units. If the archers move foward to counter, I go shoot them again. If the cavalry counters, then the rest of the standard plan works. If I mess up at any point (Like forgetting to put back Skirmish mode on when the real fighting starts, mistiming a retreat, not noticing a smaller cavalry charge against a group of waiting head hunting maidens, ect), I'll probably get beaten.

I'd say it's a good counter-strategy :) It wasn't the exact same as yours, but I faced in a 1v1 a relatively similar strategy. I won, but let just say I hadn't too much left at the end. Even a formation like that with a passive defense like that isn't hard to beat, but an active one (Short counter-attacks all the time, with 2 or more at once) is very hard to micro against. And with Skirmish off at times against formations like that is pretty dangerous I'll admit.