Brittleness and Rending stacks do not further increase your damage beyond 100%.
That is actually incorrect. You can stack brittleness and rending to increase damage beyond 100% but only on targets that take less than 100% damage before rending and brittleness.
Agreed with (basically every) ogryn heavy sweep attack being too slow. Bull Butcher is a good simple example of this, the heavy swipes have a huge windup delay before they fire that makes it difficult to use in the flow of combat. Usually I can only fit one in as an opening move before I get surrounded. Other weapons can be even worse.
That’s actually super interesting to know, thank you. I had no idea it worked like that.