I think I'm going to step out of this thread, not for heated emotions or offensiveness, just because I disagree and don't forsee that changing
So I'll step out and say, pbd, I consider whirling frenzy barbarian to be balanced.
Infiniti2000 considers it to be unbalanced, or at the very least better than normal rage.
I suggest you take the variant to your DM, say that you're interested in the variant and ask if he thinks it is balanced.
Also, because of the improved rage at level 11, my calaculations for a 14th level barabarian saves were incorrect.
Whirling Barbarian
Fortitude +9, +Con
Reflex +4, +
3 if whirling, +Dex
Will +4 + Wisdom
Standard Barbarian
Fortitude +9, +Con (which increases when raging)
Reflex +4 + Dex
Will +4, +4 Indomitable will, +3 if raging + wisdom
Also, because of the lack of Con bonus, the rage lasts 2 rounds less normally and the whirler has 2 fewer hp/level, 3 rounds less and 3 fewer hp/level at level 11 (when the Con bonus would become +6) and 4 rounds less and 4 fewer hp/level at level 20 (when the Con bonus would become +8)
If your DM does not think the variant is balanced but you still want a similar feel, consider the standard barbarian with the Whirlwind attack feat chain.