What I actually like is the whole absence of an engine tied project management. It's supereasy and straight forward. You have your script and your files and you access them the way you have them stored. Couldn't be better. (No, I'm not ironic or sarcastic. I really like it this "oldschool" way.)

I hope the new WED brings some tools for terrain creating. Everything about that is already said.

For MED: I usually use it as an importer and finetuner for MDL files. And I wouldn't care if the abilities for modelling aren't further developed, if instead the workflow for importing and handling is improved. There will always be better tools and I don't think MED will ever be able to catch up. That work is better placed on engine features.