I´m no fan of "very hard" battles, but thats another story.
I see not one slinger in your army composition - you want to kill pedites and triari spam, you better bring some with you, i´d say.
Shock cavalry is nice, lonchos are cool, but with all that "vh" bonuses...well, you could "import" some eles ( though, i have no idea if macs can recruit them outside of India at all ).
Do you like mercs? I´d hire lots of Raetians, and perhaps a unit of Gaesatae - fear factor, superb killers + 2 hp.