There's nothing wrong with that first shot. It's exposed well, composed nicely; a very pleasing natural shot.

Why do you think a polariser would have helped the second one? You'd still have a featureless sky, but it'd be grey rather than white, and the foreground would be underexposed. It needs a soft graduated ND filter. Or shoot the whole thing 1 or 2 stops under, and push it back up in post. And the biggest problem is not the exposure, it's that the picture isn't even remotely straight.

And that DPReview picture is ridiculous. F/9 at 1/200th at ISO 100? You'd literally never shoot like that in real life - at the very least you'd have a speedlite to provide fill flash. Are you currently struggling with a lack of DR?

If you just want to buy more gear, buy more gear. But the thing that's going to improve your photographs isn't more gear, it's more knowledge and more practice about the fundamentals of tekkin' pickchars.