MP surely won't let you down
Now, the problems with AI you mention are already known (if you make a quick search you'll find plenty of threads about it). The main complaints/facts are that the AI will not attack planets with space station at Tech 3 and above and it willl make fleets consisted (only) from Tech 2 ships, meaning corvettes etc.
Since we have not access to LUA scripts that describe the behaviour of AI, what we currently do is to find alternative ways to make it be more aggressive, cheat more and make bigger fleets. EaW:TR will hopefully offer a more challenging AI in v2.1.