Meh, the higher difficulties just cheat more than the existing difficulties. If you're into that, it will be more challenging. If you're not, it's pretty much the same artificial idiot that's learned a couple new tricks. I've heard the new features really liven up singleplayer, though. Diplomacy does make diplomacy that much more interesting.
Personally for me, the post-Entrenchment AI is pretty flawed because it doesn't know how to deal with starbases. I'm able to beat unfairs just by quickly starbasing choke points at the start of the game, or just starbase rushing its homeworld. With the sole exception of TEC (which will eventually build enough Ogrovs to break an unsupported starbase, though usually much too late to turn the tides) none of the AI's will ever be able to break these starbases once established.
sicne i'm scared of MP and if you don't play a certain way your bound to loose.
There are lots of ways to play online. You certainly do have less leeway against the AI, which is pretty slow to react and predictable, but that's what makes it fun against a human player. Human opponents can do really unpredictable things... like instead of building a fleet spend all their money to starbase two choke points to block off your expansion. To counter that, an opponent might run a colony-class capital ship past the starbase and colonize a planet behind that starbase line, opening a new front against the enemy. That's a real example from a game I played, by the way. Really fun match, too. Starbases and real-estate versus a two-front onslaught by massive fleets.
