I'm not sure about that. If you take a look at (for example) the awful change on Stack Overflow made by Shog9 to mitigate short comments (and what he believes are therefore bad comments), you'll see the huge backlash and also notice how many people can and do leave thoughtful comments with only a single line or less. I think it is an impossible problem to judge the quality of content by its quantity. The +1 comment is an extremely niche type of comment "problem" that can be mitigated successfully by outsourcing the functionality to a simple upvote widget, but I think that's as far as you can get in judging comment quality without making very broad statements that quash some quality content by mistake.
Honestly, Shog9 is the single biggest reason why my participation in Stack Exchange has dwindled to prettymuch nothing. It's as if he wakes up one morning and decides "I know! I'll make a huge change to Stack Overflow that will piss thousands of users off! ^-^"
What's just as annoying is that as far as I'm aware, he has never admitted that he's been wrong about anything. Ever.
