I don't quite understand what bad practice you're tilting at here, Nev.
If nothing else, GPS GoTo pointers (and their much maligned magenta lines) do, at least, keep you firmly on a given "magnetic TRACK".
(For a start, satellites don't give a damn about your local winds, nor your heading.)
Sure, in the olden days your night-before planning was all you had, to come up with a heading to keep you to a track magnetic. But as a method, it called for lots of faith in forecast winds, your old whiskey compass and your ability to read a map etc. But hey, it usually worked out and for sure was/is great sport ... precisely because it was/is difficult.
But since GPS, if holding a magnetic track is the main game then no amount of 'planning' comes close to following that 'JUST GoTo' boogey man.
Obviously there's more to the art of flight planning than that. But, with the help of EFBs etc. I'd say it's practised better and safer today than ever.
Good flight planning and magenta lines are hardly categorical opposites.
BTW, I believe we're supposed to track hemispherically above 3,000' now.