Enterprise is apparently going to have a few episodes dedicated to explaining why the original series Klingons look different than the later ones! Much better than Worf's answer of "We don't discuss that" in DS9's Trials and Tribblations!
I am very excited by these new arc-style stories. The one with Soong was great. And then the one about the Vulcan religious stuff/Reunification was nice. I think reunification is one of the few great potential stories that has been overlooked in previous series.