Part of metal ethics should be: no fucking alterations of original masterpieces. The dumbest re-issue I came across recently was the Zyklon-B EP (2004), featuring a remix of 'Warfare'. Needless to say, that song dragged down the brilliant triptych and wrecked the album as a whole.
'Bonus'-tracks not only ruin the listening experience of an album in terms of narrative coherence and duration, but are often discordant to what the album was ment to communicate. A good metal album is a mature work of art that stands on its own. Like works of visual art, an album will need room to be fully appreciated for what it is. No distractions. Silence around an album is like the frame or empty space around a painting; it provides depth and allows for focus.
If a label feels the desparate need to help sell its shit out by adding extras, it should at least have the decency to divide the additions from the main work with a pause of 10-15 seconds; this method, customary in classical releases, would give the listener the opportunity to silence the medium before the shittily-produced, third-rate instrumental sketches or other initially dismissed material fill the room with redundant noise.
I'm not a collector, but I find myself buying overpriced first-presses to avoid bonus/malus-tracks. If the material ain't worth a release on its own, leave it on the shelf. It's a matter of CULTURAL HYGIENE.