Interesting on CPW being easier due to the staggered arrival when combined with Schizo waves. Not a problem with CPW per-se because youc an achieve the same thing with CPW off by simply killing all neighboring warp-gates (all CPW does is skip the check for neighboring warp-gates). But some adjustment for distance-spawned schizo waves may be desirable, though I can't think of an obvious solution that doesn't involve changing them into something other than normal waves/threat.
I think the solution is to simply make freed ships/threat be more intelligent in general, and CPW waves will "inherit" that intelligence.
I think the #1 thing that was revealed in this little experiment is how freed AI ships deal with trying to enter into a friendly planet that is currently being besieged, instead of always charging in blindly just because it is friendly.
Also, fun things like
other idle freed ships helping out on defense.
Or even crazy stuff like if a freed ship gets near another freed ship that has chosen the same destination, they may get together and group move there, especially if one of the ships is already group moving, making sure to "regroup move" if the min speed of the group has decreased, and maybe some logic to not any one ship fall below X% of its speed, splitting the group into multiple groups if needed to achieve that. (Actually, I've seen an AI for the Spring RTS engine that tried to do this sort of "dynamic group management" thing, including merging and splitting groups if it feels like its a good idea. I think that Starcraft II's AI engine has functions for that sort of thing too)
EDIT: Semi-ninja'd on the last idea by Wanderer