I also came from the original Dinc and everything has been an upgrade, just a couple things that I missed from the Dinc from having used it for a solid 2 years.
1) I missed the search button as mentioned before.
2) I missed the menu button right on the bottom instead of top right on the DNA. I have small hands so it's a little hard to reach at times.
I think that's about it. The biggest improvements is the battery life and display. I will admit, I am getting a bit tired of Sense as coming from 2 year old Dinc to Sense 4+, it basically is the same just minor feature improvements here and there.