I agree with Lorenzo. At 1 ME they're pretty good value for the AP (far better than, say, Reg Bd (O)), at ? ME they were just too good.
But the big change isn't for armies like the Syracusans, where the Reg Sp (I) are the majority of the army - the total ME falls drastically, but the numbers of elements needed to be killed to dishearten or break a command don't change very much -, but for those like Medieval Germans with moderate numbers, where at ? ME the poor spearmen can be thrown into the fray with abandon (at +5 against most opponents they're pretty good at taking people with them when they die), whereas at 1 ME they have to be used more carefully.