Actually I had a lengthy conversation with Aris this morning; while most of what was said was in confidence I can assure you that multiple light sources aren't happening anytime soon. This graphics engine was designed to achieve x amount of fps using x amount of GPU power. There is no way currently to use multiple light sources and still stay within the performance parameters they had set.
They made a list of things for the 'perfect' sim and then had to make compromises so that it would actually run on more than a supercomputer. Using real time physics calculations for triggering active aero was important enough to them that it had to stay included. Having the AI use real time physics instead of simply running a predetermined speed on a predetermined line was another of the features that they felt important enough to keep. We won't even start on the tire model that includes graining, blistering, flatspotting, heat cycles, and a host of other things. (he actually laughed out loud when talking about seeing people call AC's tire model 'simple')
All of these things and dozens more have a cost that must be paid in the form of pc performance. When they investigated how people actually play online they found that very few (less than 5%) people actually use the night or weather function of the different sims. Everybody wants to make a lap of Spa at night, in the rain, with a tire puncture; but they only want to do it once. If you have to cut a feature, cutting something that very few people would ever actually use more than a handful of times seems like a no-brainer IMO.
