@2) Maybe in an older version, but not anymore. The installation is not as nice as in a single apt-get call, but the install documentation makes a setup a matter of copy'n'paste.
(Late) Edit: any problems I've ever had with upgrades have been related to not properly adjusting settings when moving new config files around. For example, in upgrading to 6.3 I failed to copy over my custom listen lines in unicorn for a non-standard port.
It could (and should) be more streamlined, I admit, but using diff et al. on the two affected configuration files makes the process fast. One could do it by hand w/o issues, but I wouldn't like it.