I am starting to think tight is right is very right. Opening up at higher limits is good for a lot of reasons: Opponents will have a harder time putting you on a range and you can out play people post flop if your hand does not hit.

Now in 10nl I have come to realize you do not need to protect your image, last night as an experiment I ran 8/5 at 6max, I did not notice a single time when someone attacked any different to my plays pf from when I run 18/15.
Also a lot of people will not fold middle pair or top pair weak kicker, so taking down a lot of small pots is not easy and you can run into bad situations.