High stamina is really only good for extended sprinting. The regen rate is pretty much the same as when you have lower stamina. The effect is exactly what you're seeing. It takes forever to regenerate to full stamina. That's why I much prefer high health.

Good armor, weapons, and high-health foods, and there's nothing in plains that can hurt you.

Well, if you let a starred berzerker or a 2* fuling beat on you it's going to hurt, but you can still run away from it.

I have no idea what Mistlands is like yet, since I'm still working my way to it from a new start, but I highly recommend higher health foods unless you're just planning on ranged attacks.