I would agree with you on that. I used to read a lot of sf ( both short fiction and novels ) and while watching this I felt like it was a proper sf story. I really enjoyed it a lot. It helps that it looks amazing too. It's certainly not perfect but I thought it was very good. 8/10 for me.
It's hardly running around shooting aliens is it? It's a slower burn film with some interesting themes. It's not a complicated story but that doesn't make it unintelligent. Silent Running, The Andromeda Strain - similarly simple in concept, but smart about how they go about things.
That's teh first time I've heard Oblivion being referred to as smart Sci-Fi
Compare with Prometheus. Shared Oblivions beauty but there was a lack of intelligence in the characters and what was expected of the audience.