only be played as a land grab
I take this to mean that you prefer to play with a kind of turtler strategy that you can often get away with in RTS games. While I to used to play this way the too, Sins is just set up at the basic level (though probably not intentionally) to discourage this (even if the AI was stupid enough for it not to matter once). Your resources, your research structures, your production facilities etc. all require you to control planets, and if you just allow the AI to take significantly more planets than you do, you will probably be defeated. For the first part of the game at least, all of your efforts should be on expansion for most maps, and only after you've control "your share" of planets can you afford to fortify your position and really tech up.
In short, just highly developing your corner of the map like in Rise of Nations just won't work in Sins.
