Well not just in some game but most games - you have the approach I mentioned, or a more complex approach where everything that happens is explicitly recorded - so apparently CMSF lends itself to the second approach, which is indeed far far more demanding. Obviously I realise if it was easy to implent it would have been done already, and that approach is never easy, it requires huge effort and resources. I have an MS in Comp Sci in AI, so I do understand this issue a little bit
Its a feature we'd all like to see, but if its in the far future, its worth waiting for