Concerning the second point, there is actually a pretty fascinating explanation: For a small black hole, the "tidal force" when entering the black hole (i.e. the force difference between your feet and your head) would be so enormous that you'd probably get ripped apart (so-called "Spaghettification" - https://en.wikipedia.org/wiki/Spaghettification). However, the Schwarzschild radius (or event horizon) increases linearly with the mass of a black hole, whereas the gravitational force declines with the square of the radius. Hence, for a supermassive black hole with 10 million solar masses, the tidal force is not bigger than the one you experience here on Earth (https://en.wikipedia.org/wiki/Supermassive_black_hole), and you would probably not even notice when you cross the event horizon. Fascinating stuff.
I remember having a similar thought process to all of the above, but they even explicitly call it out as "gentle" with maybe a single really simple sentence on why it was. I don't remember if they made the direct connection to it being supermassive (like they did with its rotation), but it was in the same bit of dialog.
No idea, I'm an EE not an astronomer, just guessing out of my back end.
Actually, the 2 things you noticed are not that hard to resolve:
- The quantum data was most likely never going to get out of the black hole. They executed the plan on the off chance that TARS was able to figure out how to do it if he had the quantum data. It's not impossible that there is a way to do it, we just don't know it yet.
- Your concern about spaghettification is valid, but the risk of that happening also decreases with the size and mass of the black hole. A stellar mass black hole would rip you apart instantly, but around a supermassive black hole the gravity gradient is a lot gentler. It wouldn't be comfortable per sé, but definitely survivable. You would get ripped apart inside the event horizon, but you could cross it pretty safely.
There is actually a much bigger problem than the spaghettification: every black hole has a shell of light orbiting it at the event horizon. It's light that came in tangentially, and doesn't have enough speed to escape, but is fast enough to keep orbiting. In a black hole of considerable age (like the one in Interstellar), that shell would be very very energetic. I don't know if the ships they were in would be able to survive a blast of radiation that intense, let alone the human and robot inside.
I don't think it's fair to say that they went for emotion over science. They tried to do both, and wanted at least an inclination of accuracy from the start. That's laudable in itself, in a time where most wouldn't bother with that.
The event horizon is only the "point of no return" insofar as it's the imaginary boundary inside of which even the forward light cones are oriented towards the center of the sphere (so that light cannot escape no matter what direction it's emitted in). It's not the point at which the tidal forces are so strong that matter is ripped apart (or even just your macroscopic body).
Also, from what I learned in high school physics, the body of a human would completely fall apart if it's falling to the black hole, because of the difference in gravity between proximal and distal parts.
These are just the 2 things I noticed and I'm far from a physicist. Basically, it got a couple of things right and a bunch of things wrong. There was a clear preference of emotion over science. It just seemed like "The Core" Version 2.0, but here love and reading books conquers all and is beyond the forces of nature.
I liked Europa Report a lot more even though they didn't invest nearly as much into special effects.