It's worth keeping in mind that maintainability is very subjective. We all agree that certain levels of obfuscation are not maintainable, but what exactly is maintainable really depends a lot on "for whom?"

Like you, I prefer to eschew OO (at least in Perl), but that loops back to the "for whom?" If I write code for a total newbie to maintain but only have gurus on my team, I'm essentially burning a lot of time and effort to accomplish nothing more than annoying my team-mates...