Since I made this comment, I guess I better answer the actual question: Mmmmmm-kinda.
We spent a lot of time on this issue when Lesswrong was starting out, and didn't come to any real conclusions. Visible comment karma induces some pretty big cognitive biases, and 1-dimensional karma definitely encourages groupthink, but hiding it is just so damn annoying. I've been having a hard time distinguishing the factors of my annoyance from the "boo hiss UI change", "oh geez a feature I used to use is gone", from what annoyance that might be there from an actual poor design decision.
I'm definitely for experimentation, and weakly positive about hiding comment karma; but it's odd that such minor UI changes can so badly annoy users.
I have to filter information, it is no longer possible with the wealth of information to read everything that is written and decide on its merit. The amount of news I take in daily, and process would overwhelm those who start their day with a newspaper and watch the news at 8 at night.
I hope that pg can reconsider, and add the karma back to the comments, it would definitely help me while reading HN.
Never mind...