Some people may think it's harder, some people think it doesn't. Well, whatever it is...I just think it's the same thing and asking questions like this is irrelevant. You just have to study at your Maximum and use all the materials possible.
ADA definitely changes their DAT exam questions maybe atleast every year. I heard that DAT exams have different kind of sets. (correct me if I'm wrong). Some people can get a hard set which may be easy for you or the other way around. It depends on your weakness, if you have a weakness. My friend and I took DAT the same day. He got an easy bio questions while I got out of the world bio questions. Some rumor says that there's this DAT exam with Astronomy RC on it and if you get that one DAT is hard. If these kind of information leaks probably it also reached ADA already. So, I'm thinking maybe its harder because everything are different set of questions but actually similar to the old sets.
I also think when schools evaluate your DAT they know when you took it, this year or last year.... so if you took it this year....I guess they would take consideration about the difference of the difficulty.
Anyway, I think we should pose questions like "What was 'hard' in your DAT exam that makes you think its harder, and if you were given a chance to rewind time what would you study or focus more on?"