I feel that using patterns or coding conventions to make Ruby metaprogramming maintainable is isomorphic to greenspunning higher-level programming practices with if statements and gotos. It is assuredly what a good programmer does to get the job done with the tool that is provided. But a toolsmith thinks about ways to improve the tool itself.
I think a lot of practicing Ruby (and Python) programmers are under the impression that Ruby magically solved Perl's maintainability shortcomings, and so they don't invest any effort into writing maintainable code. The result is ... unmaintainable code :) It turns out that programmers write the unmaintainable code, not programming languages.