LATEST VERSION IS UP (WE'RE PLAYTESTING THESE VERSIONS TONIGHT.)
Completely agree @Garion. People with your outlook and previous ideas (especially a somewhat previously playtested team) are invaluable to our process. I would also like to apologise. I had a brain fart and you are correct. It is a 4/36 = 1/9 chance that falls to a 1/36 chance once you claim block.
However an 8/9 chance of staying on your feet while blocking is very good for any player just starting out when he has no assists, especially when the only cost for having that bonus against any ST4 player is declaring a Blitz action.
My main criticism is that Bloodletters (and by extension, Bestigor) are stronger only for the sake of their inclusion. Without the ST boost, these models fill the same role as Beastmen. They have Horns, and have Frenzy to justify their inclusion. Never mind that Bloodletters just aren't that muscular anymore and operate as a military arm of Khorne instead of a berserk one (albeit with the sole aim of spilling blood.)
We're better off without Bloodletters. If I opt to include them, they will be exactly like beastmen in all likelihood, replacing them in the Khorne list.
The Beastman list is something I don't really have the time to test on top of the four (probably soon to be three) lists I am currently testing. Since you've already playtested it extensively, I'll leave that in your capable hands. If you'd like us to playtest it, I'll make modifications only after running it through the Dungeonbowl we're starting in a month alongside the other V2's of the teams I'm building now. Up to you. Hell, I'd invite you along if you were closer.