If you're wasting your time recruiting those crap native spearmen, it's no wonder you're struggling. Levy hoplites (recruitable everywhere with a level 1 regional barracks) are cheaper and better than pantodapoi. Long as their flanks are covered, they'll just about hold a line.
More importantly, in Sinope, Trapezous and Nikaia with a level 3 regional barracks, you can recruit the redoubtable Classical Hoplites, who are more than capable of holding the front of a phalanx so you can outflank it. They're also quite cheap, have very good armour and good morale.
A cheap and extremely effective infantry line is composed of four units of Classical Hoplites in the centre, a unit of Thureophoroi either side of them on their flanks, and a unit of Peltastai on the wings. Put everyone on guard mode, wait til the phalanxes engage, then send your cavalry around the back. Crushing victory time and again.
For added bite, recruit some of those handy eastern slingers to whittle down the enemy skirmishers and light cavalry at range before they engage, and possibly Caucasian archers if they've got a lot of akontistai and other unarmoured targets.
Bookmarks