It's actually very interesting, but I've used stealth a great number of times in red dead. It wasn't easy though. FOr the odd bounty or two I've actually snuck up behind people and lassod them one by one, or knifed them all down. VERY satisfying.
Rockstar has this bad habit of giving their AI what I like to call "The 6th sense" or "The 3rd eye" Their NPC tend to have this ability to sense the player's presence when he is about, rather than actually having to see him. I remember in GTA Vice City I would take a helicopter onto the roof of a really tall building, out of eye sigh, and pull out my trusted sniper rifled. No matter who I shot, I got 2 stars. It was impossible for people to see me.
The same goes for a "Brotherhood" Complex where the NPCs just KNOW that any of their 'buddies' in the vicinity are shot dead, wounded, whimpering, or needto call mommy. They immediately know who shot them, where they are standing, and seem to not think that a massive rock in their path will stop their bullets. they don't conserve ammo as they flank, but simply shoot and walk in a path that sometimes happens to get you in view.
Makes stealth in a rockstar game almost impossible, but if you can pull it off, it's Worthwhile and satisfying, like the giving the game programmer the finger