I have yet to start a campaign with them... but...
When I played as the greeks and Selucides Pontus always have huge stacks runnign around asia minor pretty quickly... although much of it is eastern infantry, the sheer number still made it impossible to face them anywhere else except in ur town...

From what i can judge as long as Pontus stays peaceful with the Armenian and block Selucide reinforcements across the mountain pass, they are definately in the best position to unify Asia minor... along with the fact that they can build caravans, they should be really rich if they can take some good port towns... Armenia faces a 4 way war too so with some luck they should try to go after more easy pickings like the isolated Selucide towns...

Also.. hillmen aren't really worth it early on, they only have slightly better stats than Eastern infantry but comes in less number... rather just overwhelm ur oppenet with sheer number of eastern inf... (or at least tie them up ) later on when u have phalanx though hillman might be better for their more useful abilities in small numbers.