I can see the entertainment value in AI vs AI duels, but the actual benefit does probably not outweight the work to make this happen. At the moment, the AI script is designed completely for Human vs AI interaction, even if the game would suddenly allow AI vs AI, it would potentially break the entire script (probably the same with tag duels unfortunately, which is a feature I would really like to see in the future. Coop vs AI, so I can bash some face with some friends that don't know the game too well :D)
AI replays are something I'd like to see happening as well, and if only fro a bugfixing perspective. Submitting replays of bugs would be so much better than having to take screenshots or something. However, this seems to be difficult to realize as well, and not important enough to commit a lot of resources to, as far as I know.