I don't think that it is logical that they will set the ST trilogy 100 yrs or further out. The timing issue then becomes irrelevant because 35 yrs is as good as 100 yrs which is as good as a 1000yrs if you are moving on to the next generation. They have one shot with the old cast its not like they can return in 20 or 30 years time to film the further adventures of Luke Skywalker. Disney need to make back $4billion in profit so I will assume that they are trying to bring back the OT cast because that is the safest way to kick start the Star Wars Universe of films and make that money back. It is a possibility that they would set the films further out but I'd think the probability of the ST being 100 yrs in the future is very low. That may not rule out episodes 10-12, which has also been rumoured through some media leaks or lies however you want to look at it, and that time frame setting in 100yrs after ROTJ would seem more logical to me. So you could have the ST set 35yrs from ROTJ with it taking place over 10-13yrs followed by the SST (Sequel trilogy to the ST) taking place another 35 yrs later so that would be 83 yrs after ROTJ and set over 10 to 13 yrs which would place it at around 96 yrs after ROTJ. If they didn't use the OT cast or characters in a direct trilogy would that incite a proportion of SW fan backlash. I would say that some fans have looked forward the further adventures of Luke and co as much as they looked forward to the Battle of the Heroes and would be hugely disapponited if that was taken up. I would prefer a direct trilogy but at the end of the day I don’t care that much as long as these are great films.