Good catch. This was an error in the reporting/post-processing that I fixed somewhere along the way (because when I run it now, it's working properly). It must have been after I saved that histogram though, strangely enough. Or I uploaded an old histogram.
The values I'm getting now match expectations though. For 66.7% SB uptime and 19.31% avoidance, 17.94% block, I'm getting about 22% unblocked hits. (1-0.1931)*(1-0.667)*(1-0.1794)=0.2205.
I'm not going to try and quote everyone that's given feedback, but to address most of the points:
kopcap: the "rage cushion" factor is why hit/exp doesn't drop off to 0 in value at 66.7%. Stochastic variations make it valuable for exactly the reason you've given. However, the sim is giving us pure TDR stat weights, and what you're talking about gets into the "control" scheme. Guaranteeing that you have access to it by generating more rage than necessary at other times is sacrificing TDR (in the form of better TDR stats) for reliability. That doesn't make it wrong (for example, I think it's the far superior route for paladins), but it isn't something that the sim can readily generate stat weights for. At least, not without looking at some moving average DTPS statistics. Those stats can be generated by the sim, but I haven't touched on them yet because I want to do the paladin versions first (partly because I'm certain that sim is correct, and this one is still being improved through this discussion).
Airo: Regarding SBarr prioritization, I don't track health at all in the sim (because then you have to start assuming a healing profile, and that gets even less certain). For the purpose of the sim, we can assume any value for the boss's physical DPS and assume we're getting healed through it. For dynamic SBarr priorities, we're limited to choosing based on resource, cooldowns on abilities, and SBlock details (i.e. is it up, what's the cooldown on charges, etc.). It seems like that gives us the following scenarios:
1) Prioritize based on Rage capping (use SBarr if rage>100ish)
2) Use SBarr only (low HP situation, weak physical DPS, magical boss)
The "big attack" scenario is not something we can easily model stochastically, because it requires a lot more fight-specific detail (how often does the big attack happen? how much warning do we have? do we have to plan and pool rage to handle it? etc.)
Once I get SBarr implemented, we can definitely look at both of those cases, though.
It seems like the consensus is that the block meta gem is much stronger than I assumed for warriors. As such, I'll implement it as the default choice, though I'll make it toggle-able to see how much benefit it gives.

