Bladerunner vs DADoES - spoilers etc
From memory (I only read it once a long time ago) DADoES main theme is empathy. All the humans have empathy as a religious requirement, which is why they are meant to keep pets (although real animals are expensive, so they have android ones and hide the fact from their neighbours). The Replicants do not have empathy, so can be detected by tests.
In Blade Runner the Replicants are empathetic to each other and at the end Roy saves Decker, because he empathises with him. So Blade Runner is all about empathy too, it's just that its premise is the Androids/Repliants can empathise, given enough "life" experience.
All the other stuff about whether or not Decker is a replicant is kind of irrelevant as far as I can see,