I'm running into a problem, but I'm not sure it's actually a bug, so I'm bringing it here.
Say a user has an Elpa package installed, called A (version 1.0) and would like to install package B.
Package B has a (require 'A) statement, because it uses one of A's macros. However, B lists (A "1.1") in its PackageRequires, because it uses some new feature of this macro which was added in version 1.1.