I heard that the scheduler is a huge obstacle to many potential optimizations, is that true?
I'm not a low level optimization guy, but I've had occasions where I wanted control over which threads my goroutines are running on or prioritizing important goroutines. It's a trade off for making things less complex, which is standard for Go.
I suppose there's always hope that the Go developers can change things.
If you model it in a way where you have one goroutine per os thread that receives and does work, it gets you close. But in many cases that means rearching the entire code base, as it's not a style I typically reach for.
That said, if you're greenfielding and see this as a limitation to begin with, picking another language is probably the right way.
If you need it pervasively, Go may not be the correct choice. Then again, the list of languages that is not a correct choice in that case is quite long. That's a minority case. An important one, but a minority one.