Yeah, if you were to spend time in the spam sections for an hour a day and reported all the garbage posts, you'd hit 5000 reports pretty easily.  I don't h ave quite that many, but I'm close.  I was doing much more reporting before the merit system came along and since then I've been slacking--and I don't visit sections like Bitcoin Discussion much anymore. 

My feelings about reporter badges are kind of neutral.  I do think it would be a cool thing to add, as it would be a status symbol for a lot of members and--most importantly--it would light a fire under people's asses to do more reporting.  People love to level up, you know. 

Badges certainly aren't needed, but they would provide incentive for people to do more reporting.  I have no doubt about that, because a badge would be recognition of an achievement of sorts, much like forum rank is or merits or trust.