Tyler reported an issue that eventually made me discover what I consider a critical problem.
Namely, if you are one of those 100K Jenkins 1.x users and when you upgrade to 2.0, you will not get any of the new pipeline functionalities. We positioned pipeline as *the* major addition of 2.0, so this really defeats the purpose of 2.0. This is really bad.
After talking to some people, I wrote this up as a proposal to fix this. I think it addresses the concern raised in JENKINS-33568.