It seems that another rather popular game has somehow escaped the attention. From the point of AI strength, there was RTS named KKND made by an Australian team (smthing like Melbournehouse) in 1988 or even 1987, don't remeber. C&C and AoE/AoK is a cake walk compared to KKND and not because of handicapped production or some aritficial bonuses but purely because of AI strength. The expansion, KKND II, however, is not that powerful. The point of the game was to have very simple tech tree and rules (kill them all!) and relatively few units with accent on proper tactics on defense and offense. I still play it sometimes. More modern variation is the Cossacks games which has much weaker AI but more fun due to great design and cool multiplayer tactics.