More and more PC releases are DOA, it seems like every major AAA game is riddled with bugs on PC.
It's because the consoles are easy to develop for and there are subtle differences to PC development. It's just down to shit and rushed technical departments. It's an old engine and they still can't get it right.
Oh, and I'll point this out, the problems are mainly with unlocking higher fps. If you did that on the consoles, the problems would be much worse.
So it's not well made on any machine, this is the same way they discovered Watchdogs was ropey too.
Isn't 60fps difficult for open-world game?
No, not really, it all depends what that world is doing and how they store the data. In fact thanks to lod and all that it can be easier to tailor an engine to run on an expansive world than an indoors scene.
That's a recent myth people come out with to explain low framerates, but it's not true for the most part.