The numbers on Inner Rage are very easy to adjust. I wouldn’t obsess over the current ones too much.

We don’t want warriors to sit around autoattacking until they proc Inner Rage all of the time. We also don’t want them to be bummed when they slip into it. It’s there so that if you get 100 rage and can’t spend it fast enough that you aren’t overly penalized. I realize some of you think that can’t ever, ever happen with the new numbers, but we haven’t seen enough high-end PvP or raiding to be convinced yet.

The numbers just need to be such that you play normally until you get Inner Rage and continue to play normally if it happens. Changing your behavior to try and hit it ASAP or avoid it isn’t what we’re going for. (Source)