I love reading thrillers. I’m not terribly skilled at writing the action scenes many thrillers require so I don’t really write anything that falls into that category.
I am particular about endings. It needs to be satisfying. The protagonist needs to win his quest even if the outside world doesn’t see it. If part of the quest is recognition, then yes, the protagonist needs to be recognized by the authorities. Also, generally speaking, the bad guy has to pay a price.
I prefer it if I’m surprised at the way in which this happens but predictable can work if I’ve been carried along too quickly to anticipate the ending too far ahead. I mean, I can suspect.
It also has to end. A thriller that ends on a cliffhanger will annoy me and I’m unlikely to read that author again.
These are my personal preferences and shouldn’t be taken as a how-to guide as far as thrillers. It’s really not my genre in terms of writing. Just as a reader.