If you don't care about boot times then you should have no problem with people trying to change them.
I wouldn't, if it didn't add hours to the install and config of a service that isn't available as a package from the distrubution.
And, even if a package is available, it's impossible to make a systemd dependency tree work correctly unless you install every package that might possibly be used. Based on other posts, this seems to be the assumption in the architechture of systemd.
As an example, if you have sendmail installed, it doesn't have to have clamav installed to work, and so the package doesn't have that dependency. Likewise, if you do have both installed, sendmail still can't have a systemd dependency on clamd running, because you might not want to use clamd to scan e-mail. But, if you do want that configuration, you need to muck about in dependency files that will be overwritten the next time you update one of the packages.
OTOH, with some other init system, all you need to do is add few lines to the sendmail init script to wait for the clamd socket to come into existence.