perfect mixing and bass/sub-bass
One good thing about analog and outboard gear was that you could experiment in real time. That made it a lot easier to "mix with your ears." You could try something for a moment, play around with the depth of an effect or the Q of an equalization curve and then whip it around continuously.
While real-time tinkering capabilities are finally coming online on "workingman's workstations" a lot of folks still do their mastering in a non-real-time environment so it's hard to get the feel for where to start with mix fix-ups.
One caution I'd add with regard to bumping the sub-bass -- make sure you your monitors really let you know what's going on down there. It's not the same thing but if you know what you're doing you can use various audio spectrographic analyses and 'topology charts' to scope out potential problems -- but there's really no substitute for having monitors that accurately report the subspectrum in question.
Unfortunately most nearfield monitors don't always get down there and a lot of popular monitors drop off rapidly under 80-90 Hz or so. For rock, folk, etc, this might not be much of a problem -- since there's often not a lot of meaningful content down there in a lot of it -- but for dance and club music problems with the sub-bass can be disastrous -- not only does there tend to be a lot of content from synthesizers and even extended range bass guitars (5 string, etc) but (with luck) the track might find its way onto a club or rave soundsystem and that will really magnify any problems with the bass -- or a lack of bass will be glaring contextually.
A lot of us don't much like summed-mono subwoofers but I've known people whose monitor setup included as an alternate a cheap but effective sub-woofer
mini system. They'd switch back and forth between their hi fi (but inadequately sub-bass-responsive) stereo pair and the funky but bassed-up subwoofer system to iron out problems at the low end.