What do you mean by 4x because AI War got a lot of the Xs except one. If you meant a turn based strategy games, yeah that a whole different games.
AI War got 3 of the 4 Xs:
Explore
AI War have so much scouting, a lot more than many classic 4x and it play a bigger role in the medium-term game.
Expand
You do expand in AI War, and you expand in more interesting ways than classic 4x for two reasons: i) getting to specific points is very important for special ressource and essential for victory (advanced research station, advanced factory, fabricator, core shield generator and anything else that your expansion has activated). ii) This phase is less boring in AI War than classic 4x because your expansion is actually part of a war right at the begining while 4x you usually start by expanding in empty unoccupied space.
Exploit
This is were AI War is not really a 4x. You do have technology and technology points as a 4x games but I think the major elements is really your planet economic development in 4x; building factory and research center for increasing your prodution or research output, improving your tax income and etc.
Personally, I found the Exploit to be one of the most problematic aspect of 4x games. In modern 4x, you can sometime win just by doing a lot of exploitation. In fact, having a well refined and powerfull economy could mean that the last X, exterminate, is often done through pure economic dominance and large number. A good example of this problem come from the Total War series; they got this pretty nice combat and intense combat mechanic but if you are really good at the Exploit part of the game you can make so many more units then your opponent that the combat mechanic become pointless, you just overrun your ennemies with very large numbers.
By not getting into the Exploit, AI War is kind of avoiding this problems and focus more on the the three other Xs and that the strenght of the games.
However, Exploit is a very interesting mechanic in itself and in fact many games, especially board games, solely use this mechanic to create truly outstanding and fun games. Settler of Catan, Puerto Rico, Agricola, Dominion and Caylus are all extremely popular board games that only focus on developping stuff in a turn based environment. If the guys at Arcen Games want a good design for an Exploit games that where they have to look and truly making them a bit real-time would do them good as well. Now that I'm thinking about it I'll try to come up with a board games that include AI War procedural and deep Explore and Expand mechanic into an actual board games (or maybe I should finish my other design about a cooperative board games closer to AI War concept but I feel the later would make me more money, board games is really all about Exploit these days).
Exterminate
Well you don't exterminate everyone as in many 4x, AI War follow the more plausible scenario of taking the leader and central forces which more accurately ressemble an actual war (nobody ever conquered every bit of an ennemies empire, they get the big important chunk and the rest surrender).
