With the changes to combat in .95 I wonder if fleet sizes need to be changed more than they already are since combat is much harder. Fleet sizes feel smaller already but I still think pirate doomstacks are really hard to beat even with a late game fleet.
In 0.95 number of officers dominate deployment point calculation, and AI fleets have higher number of officers if you're not using mercenaries. So most of the time when you're fighting late game AI doomstacks, you get the bare minimum of 40% of battle size as the starting DP. With a default battle size of 300 DP, you'll get 120 DP. The disadvantageous 40%-60% split can be equalized to 60%-60% in battle as you capture battle objectives, so you should try bringing fast ships that can easily dispatch enemy frigates (safety overridden frigates are an obvious choice), which should be easy in the case of fighting against pirates.