C'mon Adobe - just let me do it all in develop!
Well, lets see. The basic concept, a database/catalog based photo files management system integrated with a cutting edge Raw converter was conceived in 2002/3, call it ten years ago, and most of the code was written in 2004/5 with betas in 2006. 1.0 at the beginning of 2007 and four new editions since then that have added more features and improved old ones, but remained faithful to Mark Hamburg's original vision. I have no idea how many copies sold - a lot apparently because every poll shows LR as second only to her sister ACR. So, despite the huge success of the program, there is a very high probability that Adobe will abandon that winning formula just as soon as you send your constructive suggestions to the appropriate site, http://feedback.photoshop.com/photoshop_family
Why can't I do simple things like render 1:1 previews ...
Have you tried clicking in the the image display area or using the space bar? Works for me.
I have little reason to ever be in the library module
So you have little reason to need 1:1 library previews.
... and group photos in the develop module
I don't understand. How do you want to group them? Into batches for batch editing or batch printing? How about selecting them in the film strip in the bottom panel? Grouping them into collections? What does that have to do with developing? Why should it be in Develop?
I have to confess. I lied before. There is no chance that Adobe will completely remake the application for your convenience. Learn to work in the existing arrangement, including the shortcuts that make movement between the modules very fast, or move on to a program that suits you better. There are quite a few in the market, although they don't sell very well.