So if I make a new world space and I make a map for it for the UI, how can I make the landscape look like the map without using a heightmap? I just feel heightmaps take away personal artistic flare.

Draw your own heightmap which is the long hard way, or use some program which lets you make heightmaps/raw data. If you want to have total control over every square inch of your map, you'll have to draw it out by hand. Which if you're using an actual map.. you maybe in for some trouble. Think long and hard before starting a new worldspace/landmass. You'll be stuck in the CS for a very very long time when you begin.

Importing an existing heightmap of real landscape takes away personal artistic flair. Using a heightmap generated by a fractal world generation program takes away personal artistic flair. Creating a new heightmap by hand in the heightmap editor requires a great deal of artistic flair, since it is, essentially, painting. The heightmap editor gives you tremendous control over your heightmap, so, as Vou said, you can literally spend years tweaking your heightmap to perfection. You can use http://projectmanager.f2s.com/morrowind/TESAnnwyn.html to import your hand drawn UI map as a basis for your heightmap if you want. (Check out the images to see what it can do.)