That is true, but grabbing a group of mobs, that haven't been hit by anybody yet, leaves that buffer fairly low. A Cleave and few glancing blows, or firewall, would negate that initial buffer only fairly quick, and unless that person is standing on top of you, the mob is going to run to the person that did the damage, while your still on timer for intim. You'll have to chase it down or have them bring it back to you, and get the timing right on intim, radius etc, to get it back off that person. All in all, it sounds sloppy, and prone to error.
I understand where you are coming from on how this could be a good thing to a certain extent. I personally feel it won't work though. The game has been around for 5 years, not once was it really necessary at any given point, to concentrate on the same mob when trash is involved.
All of this is mute though, I'm just re-rolling to a pure hate tank, dumping SD, and investing in something other than intim, as its not needed to hold aggro with the hate method today, it won't be needed after update 9. While tanking in raids, I'll go auto attack and grab a snack, as it really won't require anything other than that to work