It'll take some explaining to new people about threat (110% for melee, 130% for ranged and what not), but this should be a great way to make 5 mans go a lot smoother without Salvation. Since I'm assuming it's based off of KTM/Omen style readouts, the % is the % of threat you have compared to the Tank (or #1). So at 100% you have the same threat as him/her, at 110-130% you gain aggro, wipe the group, and get QQ'd at. It'll make raids better because that will be one less needed AddOn, though Omen and other such Threat Meters will still be superior, with TPS and a breakdown of abilities, but since they'll easily work with the Blizzard Threat Meter, you won't HAVE to have a meter to get into raids.

And the stable slots? That's pure win right there.