I have played Red Alert II recently and was really PO by AI there.
Man, that AI cheats big time, covering almost all points you mentioned there, and more.
IMO cheating AI as a standard AI in the game is just a product of laziness of programmers.
However, cheating AI as a option can be a good addition to the game like SE4 because it will provide more challenge to the more advanced players (like playing on impossible level in MOO2). Maybe adding some new options for cheating (in SE3 you could select how many planets and what tech level AI has in the start) would be welcome addition to the game and make it more interesting and longer Lasting.