I think you're falling into the trap that cheap and easily available plugins have sprung.
Mastering, in the traditional sense was a necessary process to ensure that the distribution medium did not compromise the music - by looking at available dynamic range, frequency response and other features. They'd tweak the mix to try to retain the sound, when it needed to be squeezed onto media that would compromise it.
Now, mastering is another word for squeezing extra level onto the media, and in my humble opinion, if your mix sounds great, then what exactly will mastering be doing? making it better? I doubt it. Mastering can still sort out mixes that have been done badly, with band splitting and then multi band processing, to perhaps compensate for a bass heavy or bass light mix done in a studio with less good monitoring, but if you intend to master your own mixes, you've probably already have done it. My mix is complete when I'm happy. I then do NOT wish to change it. What I do do - is check the levels match, so if I have say, three loud tracks and one quiet one, or busy mixes with loads of sounds up against a vocal and piano track, I want to sort the levels out so people don't need to touch the volume control at their end. So a quiet track sandwiched between two loud ones must be at the right level, and that's difficult to do as a part of the mix - because at that point, I'm not listening to the others.
For me, this is 'mastering'. I won't be changing the dynamics and I won't be changing EQ or processing. If my mix is done, then why would I want to then change it?
Mastering is valid to get tracks at the right loudness for certain distribution pathways. I just don't see it as something separate for home produced mixes. I do see it work when the product is produced in studio A, but still needs work for distribution. My problem with current 'mastering' is that it is seen as a change in the sound process. People chasing LUFS, or wanting to add 'something'. Real mastering studios have really good acoustics that allow really detailed listening - only in this case would I want them changing the sound. If you sit down to master on the same speakers as you used for the mix, why didn't you just mix better?