Based on my experiences with Lightroom since Beta 2, my two requests are:
- Better management tools for keywords - dragging and dropping keywords into a category is OK to start with, but when your list starts getting long, management gets really difficult.
- Slideshow DVD authoring - as Scott points out, even consumer-level tools like iPhoto do a better job of slideshow generation, and Lightroom is supposed to be a tool for professional photographers. Even Lightroom's nearest direct competitor, Aperture, does a better job.
I did consider adding panoramic picture generation, but I'm still in to two minds as to whether it belongs in Lightroom or not. Others have requested it, though, so that base is at least covered.