Quote Originally Posted by Zarax View Post
To concentrate a wall of spears it requires that only so many men can be deployed in width, making the lines shorter than many equivalent formations.

Also it doesn't help the phalanx that the roman army started reforming around that period towards even more flexibility (what I like to call the "scipionic reforms"), meaning that the tactical usage differences between hastati, principes and triarii started to soften.

Another important factor is that we're talking about veteran legions, meaning more skilled and better equipped than your average roman force.
You are wrong, only one legion at Pydna was made up of Evocatii, the rest were new ensitees. I seem to recall it was about the same at Cynoscephelai.