So, I have a question related to this as well.
Mainly I have a hard time keeping wrath up. For some reason my tornadoes don't like to proc into the fray, even though I have a 65+% crit rate with wrath up. Obviously it is especially problematic in small groups because things (on mp0-1) die so quickly that the tornado + ww just melt them so I run out of fury and then have to bash for more and restart, which is really pretty sloppy and not at all what I want.
This is why I had originally veered away from wrath because I was only using it to escape CC, and I really would like to hulk up and murder some demons, but it's frustrating to have to wait 60 seconds or more to do it :/
I don't see a question lol. But yes you are correct in that assessment. It is more difficult to maintain wrath (or even fury) when playing with groups. I usually just ask the group to bump the MP up a bit. Most don't care as long as I am willing to carry the dps burden....of course I don't mind and everyone gets better loot as a result.
On a side note, you don't need tough as nails for lower MP. Your EHP is plenty to handle through MP4. You can switch that out for either animosity or unforgiving to help with fury gen. You might even consider switching out WC:I out for a fury generating skill/rune to make it even easier to keep fury.
This is a common side effect. On the bright side...I'm not one to complain about being "too powerful" lol ;)