Ok guys, about 'buffing' BW;  I was thinking about it long ago, but wasn't gonna say because of same reasons obscenitor said(but wasnt thinking on Ooze way activation): it's just that BW is too good on high lvls, and beast is already super-good dg, and it would be unfair to other dg if beast get BW buffed. However, it can be done(!) and still it would not be so much stronger on higher lvls, that it would be balls-out insane late game as obscenitor said.
Here are the ways to buff it in such a way - but bare in mind that still i wouldnt force that before other dg get their more needed buffs and balancing! :
I think it is simple; just increase the duration of BW to 10 sec on all lvls. Ppl will than have to run 10sec from beast (instead of 7) if they don't want to take that extra dmg, or will not run, but stand and fight. (Also, cd should be 20 sec in all lvls in that case)
Next, mana cost could be little cheaper; from 550/700/850/1000/1000 > 500/650/800/950/950. (just like spit) or (i like it better) 500/625/750/875/1000. !!
Lastly, Unrelenting wrath could get additional buff to 'move speed cannot be reduced' to give beast effect of having 50% reductions to stun time. (i also thought about that to put it in acclimation, by also decreasing the dmg reduction or smth else. (and, by the way, it seems that acclimation doesn't have cooldown!! it is always active, whenever sbdy hits beast over 500dmg. Thake that team burst damage!  ..I'm not sure what to say. It really seems OP)
But, i know, that 50% stun reduction also seems OP, right? Give me your opinion (i think i already know what you're gonna say 
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AND, also, not to forget, an alternate version to BW (half combined with previous suggestions; and closer to OP-ness(!) obscenitor was talking about 
      ) is to give BW a bonus move OR att speed. I know - OP!  But maybe not, if applied in small amount and very clever. 
I'm not sure myself how it would look like, i have some thought though, but dont dare to write it down yet. Little later. When a think about it more deeply.
 
EDIT: 
alternative ideas: BW deals +25%/40/55/70/70 per lvl. Ah, just smth i wanted to mention; another way to make it better for early game, but i don't think it's good idea, i like better what i suggested before. (just had to mention 
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SECOND THING, about bonus move or att speed in BW. I think bonus move would be better that att sp, if i'm to choose. That movement speed would be just +5% on all BW lvls. I think it's not much to ask. Don't think it would be OP, and definitely will help for 'enemies running from BW' at early lvls.
If att speed bonus was to implemented, it should be +10% on all lvl, cause +5% is really small amount (it isnt comparable with +5% move speed). OR that +10% bonus could be added just to Unrelenting Wrath
     Anyway, it's just all ideas i could get for if ever BW is to be getting buffed. 
Not that it relly needs to 