Yeah I liked the Karkand maps, I haven't played on the original ones though since BF3 is my first game in the Battlefield franchise. Most of the BF3 default maps are easy to memorize, because most of the areas are large but compact, but Strike at Karkand and Sharqi Peninsula are quite expansive and hard for me to play on. Great maps though.
I must say, one of the only things that bother me when I play BF3 is when I get sniped. Snipers are sneaky little devils.
I like how they split up the DLC, one for summer, one for fall, and one for winter. From what I've seen so far, it looks great. BF3 needs more indoor maps imo, Operation Metro is like the only one that's mostly indoor.