I think you're referring to North Park Mall. If so, the answer is, that's not Uptown. That mall sits between the Glen Lakes and Park Cities at NW Highway and Central Expressway. Uptown runs from Woodall Rodgers (northern border of CBD/Arts District) up to Haskell/Blackburn(Cityplace building). It contains Victory, Crescent Complex, International Centre, State-Thomas, LoMac, and the West Village/Cityplace development.
This pic gives a good location perspective
As for Uptown not being that dense, I'd agree that tall building-wise its not, but street level and actual stats tell a different story. I'd say in ten years though, it will be very dense in taller buildings. There are 8 here alone that are either in pre-leasing or under construction. Very hot market for developers.
http://forum.dallasmetropolis.com/showthread.php?t=1935
from the northern end. Endless sea of apts, condos and townhomes. The townhomes continue up north in Knox Park as well.