As a Linux user since many years, I like very much the traditional package management. I think the efforts should be put on reliability and hardware handling. I have migrated from 14.04 LTS to 16.04 recently. I am using a NAS drive. After my do-release-upgrade -d, internet was not working anymore because of systemd circularity problem. I had to learn how to create systemd configuration files to describe remote filesystem mounts.
I agree that it should get easier, from release to release, to upgrade, but I am not surprised by the bugs you encountered. On the plus side, the first 'really stable' Xenial release is due soon [1] though I can't say that would guarantee your bugs will be squashed, even then - however, it is important to log them [2] to make sure they get some attention.
My two other recent issues were with my ssh dsa key that had to be regenerated in rsa and with libnss3 update that broke popcorntime. The non working wake on lan is a many years old bug in my network driver where the correction patch was not accepted.
The focus when clicking on chrome did not work anymore (http://askubuntu.com/questions/760654/cick-to-focus-is-not-w...).
When my computer enters in sleep mode, I can wake it with a press on enter. The next time, it enters in sleep mode, I can not wake it up anymore.
I have fixed the two first issues and worked around the third one. I dream ubuntu becomes more used, but these kind of issues is blocking.