I would agree that Debian packaging is unnecessarily complicated. The raw stuff is tedious, so various wrappers have been created. In the wild you see a mixture of wrappers and lower level packaging, making everything more complicated for the occasional user.

I started with Debian (not as a packager, but just as a technical user who occasionally wants to do his own stuff). Years later I was forced to use rpm and was suprised that things could be so straight-forward. Yet years later I was forced to look at Arch and was suprised again: Hey, you can understand all of it just in a couple of hours.

Accumulated experience might result in a slightly biased perception. But I still believe the described gradient exists.

The difficulty of figuring out exactly what you need to do is part of the problem. It's hard to shake the feeling that you don't really grok the build system.

But in any case it's never been as easy as just running that one command for me. Actual example from my bash history:

    $ apt source packagename
    $ vim path/to/broken/file.c
    $ dpkg-buildpackage

Now I get an error: "aborting due to unexpected upstream changes".

    $ dpkg-source --commit

Make a changelog entry for the changes you made

    $ dpkg-buildpackage

This fails with an inscrutable error "dpkg-buildpackage: error: failed to sign .dsc file"

If you know what you're doing you realize that you can just ignore this error, it doesn't affect the built package. If you don't, you have to search around and then build it again with

    $ dpkg-buildpackage -uc

So it's not, like, the worst thing in the world but it doesn't go out of its way to be intuitive either. It's hard to find good help on what to do (the man pages are arguably too detailed to be useful to people who just want to make small changes), and hopefully you didn't follow a rabbit trail with debuild.

What package and how complex is it?