If I'm not mistaken, they also use MotM to make it so mobs don't spawn in picks, mobs with motm have faster respawns (especially in classic/kunark, as they are 'new' mobs with the buff, not a buff added to an old mob). They use MotM flag as more than just a 'buff'.
The only place this would even be a problem is fire/GE. Every other raid zone doesn't have enough people in it to spawn picks or maintain a pick long enough for raid targets to spawn.
I think the OP main point was to take this trival content, and make it so its not just a HP slog fest for 30 mins with a small group. the content is trival a few expantions out, the loot it drops is in many cases (mostly trival) and on the AoC Progression servers , hardly a factor as if you want the look you will still get it. As such, it seems fitting that the "Buff" or whatever you want to call it should be removed X expantions out. it could even be replaced with a new "Buff" with no stat effects that keeps them from spawning in picks.
The sublime way of adjusting things is to tweak each encounter. This is obviously a ton of work and of no value to existing servers. Plus you have to redo it any time a global change kicks the whole thing out of balance again. MoTM is a mechanic that can be toggled off or on whatever they deem it needed on. They can tweak the mechanic (there is a couple of versions of it already no?) to use in any needed era for any future progression to deal with changes in the global game. MoTM V.11 on TSS era raids on a progression server 5 years from now? Maybe be absolutely needed. There are far worse alternatives. MoTM isn't really about creating a challenging experience, it is more about not having a handful of tactics extremely trivialize the content. Imagine for a moment a progression experience where all improvements to pet classes were 1999 reverted and it was era-set to OoW to get it all back instead of MoTM impacting specific raid encounters --we'd see almost no one playing summoned pet classes, certainly not on raids.
