The use of procs in the default engine does suck, but Procs require around as much memory as a method, so aliasing another script's methods will produce similar results. And heck, I did a quick benchmark (synthetic of course) on Procs yesterday, and an array of 1000 objects similar to what I told Ryex to use only consumer a little over 1mb. Assuming that the average user only uses around 10, that's almost nothing.
However, in a true game design environment, that would be horrible, horrible practice, I concur, but in RMXP it's not that big of a deal.