"i believe they mentioned in one of the earlier dev-streams that the A.I. would always play to the best of its ability and the difficulty slider set at the beginning just gives the A.I more or less resources compared to you"
Found this also mentioned in the forum, and like the idea if for not other reason then only due to the sheer effort that needs to go into this concept from DEVs. Think it is better to put that effort in refining the AI to be more capable
"you could say that the AI IS only human, since it is being programmed by a human (or two, let by Brad Wardell"
Agreed if the AI is using the script of a DEV since I do not think that the game will build an analytical DB and filling it with data during the game 
It is supposed to do just that with the online connection and pulling statistics and tactics from past games though.
It is of course difficult to say how it will turn out without knowing what exactly the plan is but analyzing past game statistics can easily lead to a repetitive and even less capable since in complex situations there is usually no perfect way of doing things. In such situations if the AI goes for a pattern, the user simply takes another pattern. In a game of rock-paper-scissors there is no winning pick but if someone always makes the same pick or can be easily lured into making that pick or is deductible - there is no challenge
I was actually trying to say that being random or taking the less logical route in some cases makes you more competitive. If the AI were always another human it would almost be the perfect AI to play against
"Why would the an take a less preferable course of action"
Because there is no perfect strategy to go with and if the AI thinks there is, it will probably loose to an average player due to being per-determined.
It also becomes a problem if 80 AIs from 88 are following the same strategy because that is according to statistics the way to win (it may be statistically correct but 79 of them will still loose )
Also for making the game more life-like. Intelligent beings are not logical but highly efficient partly because making mistakes does not always lead to loosing altogether. Consider a game where the AI is hammering planets with effective wings of rocket ships and in accordance with statistics and empirical effects it will continue to produce the same ships only to be annihilated by a single new type of ship the player has produced. Works 10/10 in GC2 - need to invest into defense against the preferred weapons type of the AI and produce 2-3 such ships, experience will take care of the rest. Now consider an AI changing or even mixing its layout seemingly in random interval and random strategy
If the AI goes after statistics it will always accustom its strategy to the past which in a rock-paper-scissor fight does not help much 
