It seems to me after about 25 or so games (all offline so far--still haven't got my build order or metastrategy worked out like I'd like to have for online play) the game follows one of two prescribed paths:
Either I kick his (or their) ass(es) or mine gets handed to me in fairly short order. In larger games, things usually remain more or less strategically static until I bust open my first opponent, at which point it becomes an entertaining if one-sided campaign whereby I pick apart the remaining factions one by one. This is all good fun don't get me wrong, but I can't help but feel as if there's not much middle ground between being
challenged and getting my
ass kicked. In the games where I choke and die, the writing is usually on the wall as early as my second or third engagement and I lose interest pretty quickly when an Economist or Fortifier (!) AI sends as big a fleet as possible at me as soon as possible, which isn't behavior I'd expect from those presets. Sometimes I feel like the AI personalities would be more accurately described as "Rusher, Rusher, Rusher and Rusher" although this may simply be a function of my habit of playing Unfair computers lately and maybe not having a good build order down. Once I got the hang of the game Hard was just too easy, but the Unfair AI seems like it is sometimes too.
I tend to play locked teams and I don't know why anyone would play with pirates active. When I don't play locked teams, it's usually not too hard to finish the missions and I habitually plan out my alliances to maximize my strategic position (of course). The old trick of jumping my fleet to a friendly homeworld and declaring war is fun, but they should do it occasionally too!

Also, I've noticed that when I load saves, my game has developed the habit of unlocking the teams regardless of my settings to the contrary. Usually when I load up an autosave or a savegame from a locked team game, the first thing I hear is a diplomatic mission from one of my would-be adversaries. Anyone else experienced this?