Yes, I'm that guy who doesn't like GTA. Have your laugh and get over it.
Anyway, I was wondering if RDR2 isn't just some 'GTA with cowboys' because it looks fairly interesting (which I also thought of GTA). The game looks good but seems to share some gameplay mechanics from previous Rockstar games. I don't want it to be another Do-whatever-you-want simulator because I prefer an interesting story too.
Red Dead Redemption 2 is an Open World-game, but you can only play the main missions - if you want ;) The game is very detailed. It's definitely one of the best games of the year (my prediction), maybe even the best with Spiderman and God of War.
If you like a big living world with great story, fantastic details, lots of animals, possibilities or cowboys = then yes, enjoy it :) Personally, I'm not a fan of cowboys - but I want to play the game. "Rockstar Games" is known for strong quality :) ps. And it also has an online mode.