Totally not an issue in 25 mans, but with the raid-makeups of 10 mans I've been finding myself instructing other tanks to take on more and more bosses while I cleanse. I eat a marked DPS drop, down to 1200-1500 -- which is still enough to generate the threat needed as a safety-net for the other tank -- but consistently score at the top of cleanse charts.
Now, I've always been a fan of cleansing myself when pure threat production (ie. strict rotations) aren't needed and have always helped healers out extensively in 5 man content with cleanses, but it's not something that's been neccessary in a raid setting before (beyond self-cleanses). If it were just a matter of lazy raiders they could go DIAF, but with some raid makeups it can actually be difficult for casters to keep up on them. Especially so for Diseases it seems.
Is this something other tanks are experiencing?