I disagree with the assessment that Deckard possibly being a replicant takes away from the empathy premise of the movie.
After all, the empathy test itself was designed by humans; who applies it is irrelevant.
The central point of the film is that yes, the replicants can be more human than humans — and perhaps they are.
And that the fundamental cruelty isn't even treating replicants as disposable or slaves — the replicants themselves know their worth better than that, and it's the obstacle the main characters ultimately overcome.
The fundamental cruelty is the core premise that the replicants pay for their superhuman abilities with shortened lifespan - an irreversible choice that was made for them.
And at the height of their self-realization, everything that the replicants are is yanked away from them.
All of that will be gone — like tears in rain.
The movie raises the same question as Flowers for Algernon, and is ultimately a very human one.
After all, we have many examples of parents training their children from a very young age for stardom in a particular field — at the cost of depriving them of the choice. Like Tyrell, they think it's worth it; but is it right?
The other side is — given that the replicants are beings who burn twice as bright, the kind that can walk into Tyrell's office and greet the most powerful man with "Hello, fucker", the kind who get to see starships on fire on the shoulder of Orion — are they justified in feeling slighted?
And if Deckard is indeed a replicant — isn't he arguably the more boring one, being effectively just human?
And if the viewer were to discover they are a replicant - which kind would they rather be? And if they are human, then what's the point?
The famous monologue was semi-improvised by Rutger Hauer, and that speech alone adds more meaning to the movie than the author of the article allows themselves to see.
The speech is ultimately Roy's last and ultimate gift. Deckard may not see starships on fire at the shoulder of Orion, and yet those moments won't truly be gone, because he gets to live the carry on even as Roy burns out.
The scene gives an answer to the questions above: that however we were created, there is a meaning to the each life lived; and that ultimately we need each other for that meaning to exist.
For we need memories to be ourselves, and memories are need us to carry them.
The replicant/human distinction, in the end, loses significance.
The climactic moment isn't that Deckard is a replicant — it's that in the end, Roy spares Deckard's life to tell his story — and pass the torch.
It only makes sense for Deckard to be a replicant — something that Roy would know, and choose not to tell.
But whether Deckard is or isn't a replicant ultimately doesn't matter, because the film makes sense either way.
And that's the point in and of itself.