two things i see right away
after putting ubuntu touch on a Asus Nexus 7 Tablet i see the boot screen will boot only in the landscape mode and when i put it in the desktop mode i wish it
would have stayed that way the next time i boot the system, going to put it on a phone and i hope it works different but i am not counting on it, if it don't that
would sure be a couple of things to change
The login screen is always shown in the 'native orientation' of the device it is shown on. For tablets (or more accurately any screen size that is larger than some threshold value) this will be landscape. On most phones it is portrait. The real issue is that the login screen does not rotate based on the orientation of the device. There is already a discussion about this in the issue tracker. Maybe you would like to add your experience / expectation / point of view.
The desktop issue is an interesting one. I would encourage you to check if there is already an issue raised against this on GitHub, and if not, to do so yourself. At the very least it will get the conversation going.