WW with below 1.42 unbuff aps is pretty bad. My thread here gives a detailed list of what BP you should aim for to make WW a complete faceroll experience in all situations: http://us.battle.net/d3/en/forum/topic/7199962320?page=1
In all cases, your TPS (ticks per second) needed to maintain wrath depends on your passive selection, buffed CC, how well you place tornadoes, and latency.
For a single 'fat' target, like Azmodan, you can place 4-5 tornadoes out per cast of sprint. You need to be above these TPS values for perma-Wotb:
(4.5 tornadoes hitting each second)
55% cc - 6.2
65% cc - 5.2
75% cc - 4.5
These numbers above are your minimums to make the spec work 'good enough' on trash.
For a typical single elite, maintaining 3.5 tornadoes on the target is doable. In these cases you need:
(3.5 tornadoes hitting each second)
55% cc - 7.4
65% cc - 6.3
70% cc - 5.8
75% cc - 5.4
For the worst elites that move around a lot and scatter, 2.5 tornadoes is about typical. The requirements go up again:
(2.5 tornadoes hitting each second)
55% cc - 9.2
65% cc - 7.8
75% cc - 6.7
To factor in animosity, divide the above numbers by 1.2 to get the required TPS. Most WW barbs using killing spree will have ~75% cc fully buffed. Use of cold SOJ will turn the 'worst elites' into a 'typical elite' and 'typical elite' into Azmodan. So, users of cold SOJ should ignore the last recommended tps values and aim for the set above. There's nothing wrong with getting even higher tick rates, but it's unnecessary for making the spec work.
Now, these number above are 'conservative' in that they do not include fury from damage taken or maximizing the fury you get from overpower (i.e. only casting it when your fury is low inside a dense group). However, they also do not include the effects of latency, which can substantially reduce fury generation. So if your latency and skill with the build are very good, you can get by with less than these values.
For most of us, you need to hit 6.7 tps with 75% buffed CC to make the spec very smooth in virtually every situation.
1.00 aps skorn hits 6.0 tps with 57% ias.
1.10 aps skorn hits 6.0 tps with 41% ias.