As said above, is probably the most RNG-dependent mechanic in the game. If TfB doesn't proc, it leaves the warrior ragestarved and doing no damage, and when the mythical 5 stacks are up, people will get globaled. Literally.
A lesser problem, but still very annoying. It's never nice to be so damn RNG dependant, and TfB building up Heroic Strike damage makes it directly compete with Slam. This leads to that when you have way too much rage (which still happens), you don't know if you should Heroic Strike to dump that rage, or wait until you have nothing else to use than Slam. And if you guess wrong, you'll be punished by getting ragestarved, or having rage capped and losing potential DPS, which feels bad and wrong.
Arms also has scaling issues, from what I've heard. Give Overpower 3x the Crit chance it normally has (equals to about the bonus 60% it has, at least with this gear level) and make it so that Overpower crits build up Taste for Blood, stacks up to 10.
Add a new ability; (inb4 reused name xoxoxo)
Consume current stacks of Taste for Blood, increasing your damage done by X% for X seconds for each stacks consumed.
Or SOMETHING! The current TfB is driving me crazy! Dx