I didn’t mean to say that it stacks more bleeds as if it refreshes the existing Rend and adds another stack of Rend on top of it, but it seems like as you add more bleeding damage on a target, it all gets dumped into a pool that then ticks periodically for a portion of the remaining damage in the pool. I tend to refer to this pool as Total Bleeding Amount because that’s how Rupture phrases it. Rupture pops on the target for whatever is currently in their Total Bleeding Amount pool. “Stacking bleeds” was meant more as “hitting the target with more bleeds to make their Total Bleeding Amount larger.”
Applying Rend to a target that already has Rend on it still has big value. If you cast it twice in a row quickly, the second merges with the first for a larger Total Bleeding Amount. You don’t need to immediately Rupture to clean the slate for the second one, it won’t waste the damage. It’s plenty viable to play without Rupture and just focus on Rend, letting things bleed out on their own instead of popping them.
But on a target that doesn’t immediately die from Rupture popping those bleeds (like a world boss, or any other boss with a lot of health), there isn’t really a lot of value in Rupture because it just makes the damage that would happen in 5 seconds happen now, with a kind of slow animation. You could just focus on building more Fury and casting more Rends instead and probably do more damage overall. The only real value gained from Rupture in a fight like this is from the secondary effects of the modifier talents, like the heal or the attack speed. That just feels weird, and is why I think Rupture should actually do more on its own, like have a multiplier on the bleeding damage it deals it pops, so that it is actually more worthwhile on those longer engagements to fit them in regularly. Right now, the only time I feel like it makes a difference to Rupture on a big boss is fitting in one big burst when it gets Staggered and takes bonus damage.
Side note, I got a second Fields of Crimson last night. It’s still like 100 base item power below the weapon I’ve been using for quite a while now. The ranges for item power are getting really annoying. But it also rolled really really poorly on everything, as if it wasn’t a bad enough unique already.