How many people (I am certainly one) skipped on replacing their original/iPad 2 with a new one this past year because of the lack of Touch ID? If my next phone is going to have it then I want it on my iPad too. I can't imagine I was alone on that.
Count me as one of those. I'm on the "non S" upgrade cycle for my iPhone so I know my iPhone 6 will have it and I wanted my next iPad to have it as well so I'm not buying one until it's included. My iPad 2 is getting a little long in the tooth though.