I see no indication that this was a to down forced decision from management (just from having talked to some developers at Gamescom a couple of years ago).
The concept really wasn't horrible it just looks like it now having seen the product, but a stealth have themed after Gollum is not a dumb idea.
There's lots of stuff you could do, like e.g. use the ring for temporary invisibility but at the cost of losing some e.g. sanity resource you need to recover.

The problem with this game is that the idea being bad doesn't even really factor into its quality since just the actual bare-bones graphics and fundamental gameplay is so broken that the lack of original ideas isn't really a factor.

If this was just a no-thrills e.g. thief clone with a Gollum skin, nobody would bar an eye. The problem is that even this low bar of "some stealth game+Gollum" is not reached.

In fact, we have a very direct comparison to a different "Gollum like stealth have produced by an indie developer" that was a smash hit: "Styx: master of shadows" is a climbing based stealth have featuring a small green goblin like protagonist that has to deal with a powerful but risky to use substance.