I don't understand why you would want a development package on the Edison. You should be developing on a real dev machine and flash the code into the Edison or any other micro for that matter.
Yocto is hard to use, too hard for most probably, but I like being able to slim down my OS to bare minimum so I can fit more of my code on the Edison. Say you build a robot. Why would your robot need to run gcc? These things were made for, as they say, the IoT so automating anything and everything you can think of but once your code is done, you flash it and let it do what you made it for.
ThreadX is like that. You only build in what you need and leave the rest of the code space for your code. The Edison isn't meant to be a desktop or tablet replacement. These are brains that make stupid things smart but it takes a bigger brain to make them smart. I like the Edison and hope it continues. It is powerful and relatively cheap compared to the Arduinos, which are far too expensive in my opinion.
I am mostly working with the Freescale FRDM-K64 and the Edison now because they are far less expensive than the Arduino products.
Just my 2cents worth.
Tim