Why doesn't Rockstar make another survival horror game...

That's his peanus weanus

It focused too much on the executions, which are the highlight of the game for me, the atmosphere wasn't especially tense, since you're the scariest thing in the game halfway into it, and you never felt especially outnumbered or fucked, as the encounters were mostly based on really iffy stealth and encounters featuring a couple enemies at best,

Even back then, Rockstar was close to a mutiny because most of the staff felt sick working on Manhunt1.
It's still a fucking stellar game though.

I just want a gta with lots of horror and just general creepy things in it, the ghost on the mountain, the serial killer sidequest, the markings and shit on top of mount chiliad and the cult related stuff are examples of the kind of stuff from 5 that I would like to see more of

It's a great game.
It's kinda sad that the game itself was overshadowed by all the controversy about the violence. I worked at EB Games when it was released. This is the only game where the manager outright said "you HAVE to check the age of the people buying this".

The game is more than just violence. You feel vulnerable as hell at times and the enemies can be some scary bastards. It has some solid stealth gameplay - I love the way they included the mic into the game, if you wanted to use it.
That said, I do think the violence was a nice "reward" when you finally got an enemy where you wanted him.

Well son, that's not a tail, it's his dick.

And even if it wasn't, pig tails come in 3 different types. There's curly, kinked, and straight. It's thought that curled tails were bred into pigs when they were domesticated for aesthetic purposes or to make it harder for other pigs or animals to get into fights and rip their tails off.

Actually I feel rather ambivalent to it.
I played it in 05 or 06, we just got "fast" internet in my bumfuck nowhere village and since it's banned in my country, I had to get it via filesharing.
I had watched a tv report on it, which only made me want it more - I was one of those edgy gore kiddies who religiously watched all splatter and gore movies one could come across.
Anyhow, I finally got it. Playing it was even more tense than fapping, as if I would be caught fapping, well, awkward but no biggie (and I didn't use any "hardcore" stuff back then), but this one would have gotten me in big trouble.
During my very first playthrough, I was thrilled by the difficulty; it was one of the hardest games I had played until then, especially when the soldier type enemy began to fuck my shit up. I distinctly remember the subway part with enemies behind doors; I think I have tried it ten or twenty times.
The violence on the other side... It became boring. You can only bust so much skinhead skulls before it becomes stale. That fucking scrapyard. Sneak behind him, wait for the red cross, batter his head off, repeat. And later with the soldiers I wasn't even able to do stealth kills and I think it was the mansion backyard where I just blasted my way through as much as I could.
Some years ago I tried to replay it, but I already got bored in the first level or so.
Now these threads made me want to try it again, but I am still sceptical.