And VC, shouldn't we be a little more suspicious of the official account of the Galatian mercenary rebellion, given by court poets and historians of Ptolemy II himself? They may well have attempted some sort of problem, sure; most likely they demanded their wage, which was what the mercs serving Antigonos did. For Ptolemy II, killing them could have been more beneficial than dealing with them, especially when everyone else is being called Soter and he is no longer planning a campaign against Magas. And he did indeed use the victory to justify/enhance his rule, as the Galatian shields figured prominently from then on in his coinage, and on the main displays at the first Ptolemaia. The Delphic Hymn by Kallimachos also uses the victory as part of the justification for Ptolemy II's rule, and as a connection between the Lagids and Apollo.
Opportunism; what I'm saying is he didn't immediately evaluate or orchestrate the situation along those lines.

But why would he slaughter Galatians for demanding their wage? These are people the Ptolemies employed for a huge amount of time, and what would future and current employees think of him for arbitrarily massacring mercenaries after asking for their pay? Besides, Ptolemy could certainly have afforded their expenses; heck, if they asked for coined money he could have given them estates. The Ptolemies had certainly not reached a point of such financial straits.

You guys are overanalyzing the situation; even if the event was used as political propoganda, it was just capitalization on the natural events. In any case, Ptolemy II didn't take Soter as a cult title, as he'd already had one - and only one of his contemporaries did use the epithet "Soter," so he could hardly have felt inadequated (his campaign into Aithiopia probably enhanced his feelings of self-worth). Beyond the almost universally accepted fact that Kallimachos' description was just some serious butt-kissing to his established patron, these soldiers were loaned to the king by Nikomedes, and had no particular loyalty to Ptolemy or any substantial expectations - thus it's hardly unreasonable to say they rebelled.