Proudly, I give to thee canivete, the Ruby Ultimate Utils gem.
It doesn’t ends with world’s famine, but at least allows you to mark some methods of your ruby objects as deprecated and they will spit a warning every time you access them.
I think it has room for more – have you any idea to share?
gem install canivete or grab source code here
edit: I needed to change the name from ruutils as a gem with a very similar name exists (rutils) – thanks for pointing out jastix.