The AI is not too smart.  ZombieRus and some others are actually working right now to make it play smarter. 

You will want to try Mods--Distant Stars and Maelstrom have tougher units in them as do other mods. 

Playing online is best with other players unless your game is laggy. You might ask here for European players to identify themselves.

Play on the hardest difficulty settings with pirates on--might make for more of a challenge--place the AI's on the same team against you as well.

@ Darvin3 : You're right ! Have a good night !

I know that the best, as it is in most strategy games - Civilization, Game of Thrones, Shogun II for exemple, is to play against people. We are far from having smart AIs that could be of some challenge to humans, unless they are granted a certain amount of cheat - which is not very funny. That is in fact weird enought, since computers are beating humans at chess, and have a pretty good level now at very difficult games like go...

The problem is that what I enjoy in that kind of game is to think, to plan, to find out the best and the shortest way to develop my civilization, to discover the correct balances between economy, resaerch, fight.. By the way, I am poorly gifted with reflex and reactivity. That is why I spend much more time with the game paused than with the game running... I'd be a very bad and boring opponent for most players !

Thank you very much for your answers.

Why not have an Ai that spams LRM with carrier caps and avoids suicidal tendencies on star-bases? Easy to program if you ask me..

Actually, it wouldn't be too difficult to change the aggressor to spam LRF instead of LF like it currently does, which would significantly increase the difficulty.  "Not suiciding on starbases", though, would be a lot more challenging.

Chess is a discrete game by its nature, meaning it's easier to break down your options algorithmically.  In a RTS game, there are so many possible factors to track that you need a fairly sophisticated algorithm just to identify which factors are relevant, much less to actually determine your best course of action and how it fits into a long-term strategy.

More important is multi-tasking.  I have an abysmal APM (at least compared to most active competitive RTS players) and still maintained diamond league in Starcraft II while I was active.  Unless you're aiming for E-Sport level competition or something you don't need crazy reflexes to play RTS respectably.

A potential problem is that you're assuming that brute-force (analyzing all possible movement options, in Go or Sins) would be needed to create a very strong AI. Although I'm not familiar with Go, at least with Sins it's possible to create well-defined strategies that an AI should be able to carry out as well (reasonably easily, in theory at least). If, of course, the AI is moddable enough, which at the moment it is not. And there aren't actually that many strategic options, even at the upper levels of play, I think - sure, there are dozens and dozens overall, but for any given situation there are probably only a couple or 3 or 4 worth considering, and I would think that an AI would be able to weigh them and come to an optimal decision.

A computer would also be able to queue up the proper units to counter enemy fleets more efficient than any human player, probably... and optimal in-combat micro isn't very complicated either, probably something a computer can do pretty well also. Broad scanning of the battlefield and making conclusions about what to move where could probably be done somewhat better by an experienced player than a computer, but making the computer relatively skilled at it shouldn't be too hard.

Making an AI very skilled at macro though would be difficult though, I think. Not impossible, but it would take a decent amount of work. I think. Another thing that plays into this is expectations about player skill (and subsequent build decisions), which a human can do pretty well but a computer can't.

So although there are a virtually infinite number of possibilities for a Sins game, I still think making a very very strong AI would be viable, if the AI can be given the appropriate amount of CPU time and if the necessary variables and commands are at our disposal.

But unfortunately, the devs have not opened the AI up to any significant modding... and the AIs are still stuck on the level of ramming their hapless fleets into starbases to die. Modding a normal Sins AI to the level of one of the top-tier players (or better) would be my dream, but we don't have the tools at our disposal to do that...