You are absolutely right in everything you said, specially about the plugins,
in my personal opinion when i started using the Calf plugins, they just
blowed my mind away, they have such a good sound quality and are so powerful
that they just make you laugh at most of of the propietary ones out there,
including the so famous and sometimes overrated and overpriced plugins made
by "waves". Calf plugins are kickass in lot of aspects and they are not only
libre but also gratis... you cant ask for more really.
As another personal recomendation for anyone interested, specially for those
who likes to compose, Rosegarden is a great alternative too, even when most
people think of it as just a good tabs/partitures editor with "basic" audio
editing functions. Its indeed a very powerful and flexible MIDI sequencer,
that gives you lots of different ways to create lot of projects with it.
Specially since using JACK you can use Rosegarden along with any kind of
plugins and virtual instruments and etc. and plug everything into a
Rosegarden project, and make everything sound great and create really cool
things with it, and if you need more then export it to Ardour or others and
improve everything further. No limits in what you can do in gnu/linux.
Cheers.