I've been reading up on the late Ptolemaic army in Griffith's The Mercenaries of the Hellenistic World and Bar-Kochva's Seleucid Army book. From what I can tell, the phalanx really degrades rapidly during the 200s BC. The recruitment at Raphia was abysmal, and by the end of the century at Panion it appears that they only had ten-to-fifteen thousand actual phalangites. After the phalanx was smashed at Panion (the Aetolians managed to flee, not that it did them much good in the end), I'm not sure they ever fielded a phalanx again.
Based on that, should we try to phase out Ptollie phalangite recruitment after a certain point? If so, what point? I'm trying to figure out the best way to do this while not being too heavy-handed.