First idea - no. we use "use" and compile time to load all stuff before "fork" webserver and to save memory with COW, so every module "use" maybe 80% of other modules.
Second idea - yes we already do this. We run map collection once per day (before Devel::Cover is so slow for us). But when map changes, it actually can break things for rest of day. So we run map collection once per day, but also do git-diff to the commit where map collection was made, then there is no possibility of use of wrong map then, but diff gets bigger during the day. So we're looking how to speed up coverage module.