So I'm looking at upgrading my main box to Excalibur, did a backup
machine earlier, performed "usr-merge" first followed by "apt-get
dist-upgrade", and so far it's working fine....

Philosophically I'm skeptical of the merged bin/sbin/etc idea, but
mostly on the grounds of "if it ain't broke don't fix it".  It kind of
irks me to be told I have to do that, but it actually simplifies the
directory structure a bit.  On the other hand, the multiplicity of
partitions/disks made sense when when a 5-MB hard drive was a major
investment, but these days my /home gets its own multi-terabyte drive,
and the whole rest of the operating system can go anywhere that the
machine knows how to boot from --- a 16GB usb drive is way overkill for
a basic productivity system, for the price of a Happy Meal.

And if I understand it, it's just a few command chains like "rsync -a
/sbin /usr/sbin && rmdir /sbin && ln -s /usr/sbin /sbin".  No big deal?
So is there any downside to the usr-merge, on today's systems?