I have been shooting all panos vertically for a long time. Even hand held without a tripod. You have the advantage of more foreground, and more sky but you have to compensate for the high dynamic range from the sky to the foreground which is...
I do all of my panoramas manually. I use the grid, and overlap by 30% for each shot for a total of shots needed to cover 180 degrees. E.g.: I shoot each image manually, and therefore, I can tap the screen to focus before each shot.
To...
Are you getting images that aren't properly focussed?
Fun fact ... you can shoot panoramas all by yourself without using some lame automated feature.
It gives you a lot more creative control.