I didn't remove the gap entirely, I tried to fill it in with some smaller mountains to make it more of a wide pass, as opposed to a monstrous field. As for the boxiness, I must be blind to it because I'm not sure how you mean. Rotating everything 200 degrees would essentially be flipping everything overThe rivers and the rain shadow look a lot better.
Personally I kind of liked it better wtih the gap in the mountains and have something similar in my own map. I think it's pretty easy to assume that tectonic plates and mountains work differently or might have been made by magic or a slain army of giants or something. It's just the rivers and rain shadow that made me feel dumb when I made mine, since water is still, y'know, water.
On another note, there's a bit of a boxiness to it. A lot of maps have that quality. It happens because you're working on a rectangular screen or a sheet of paper. My map is different than yours of course, but I had to rotate it like 200 degrees and flip it to get rid of the boxiness. Then I had to redo a lot of things to adjust to the new north and south. You've got islands, so you'd probably want to tinker with flipping/rotating/adjust each island separately. I wouldn't consider it a must, though, the way I would have with the other things I mentioned. It all depends on how much you want to put into it.