I wouldn't be surprised at all at this point if Thrash's bleed is affected by haste. It seems that it may be coming, or at least tried, in beta to see how it works out. I think Blizzard's design intent for haste and Guardian tanks is for us to get to the point where we have a comfortable rage generation per X period of time, enough to cover every rage consuming ability we need to or want to use in that time frame, and then move on to other stats for other reasons, whether they be defensive or offensive.