Give this new system a chance!
Having reservations about something, does not mean I'm suddenly going to drop this game like it's a turd sandwich.
It's look more realistic. Like in the real life ... when you missed your moment ... you missed your chance ...
Your reasoning for it being "more realistic" is sketchy at best.
For the pictured example, stealth would be using patience, and slow, steady movement. No "missing your chance" there.
I question the reason for adding any stealth mechanic, or character skills or minigames, when it hasn't been a part of the game at all so far.
It's like with the upcoming Call of Duty game throwing the traditional single player campaign to the wayside during development, just so they can jump on the Battle Royale game mode train.