I think a lot of people try to second guess Festool, when it comes to buying a new Kapex, because of the large investment. I asked my local rep directly before I made the purchase.
Last year there were rumours of a new model coming out because of the Kapex sale in NA. In Aus the price of the Kapex went down by $100, hence more rumours there must be a new model coming out.
I believe that the Kapex is in a class of its own as a 2nd fix mitre saw and yeah a few improvements wouldn't hurt but can't see the urgency for a new model, just my opinion.