(Ive done all of these things!) The more that a card is marked, the less it is worth, since its no longer perfect, or close to that
Lurrus of the Dream-Den Lurrus of the Dream-Den is not only a powerhouse in Constructed but also a top-tier card in Limited
Both are basically three destruction options in one Scheme and offer nice card advantage over time for targeted removal
If you're playing this card, you'll certainly want Goblin Chieftain or Warchief in your corner, as Muxus can then swing out the turn he comes down and finish the game in one fell swoop
While it will be attactive to run him in the command zone, he will also be right at home in countless aristocrats and tokens builds, especially those with Commanders and gameplans that involve sacrificing many creatures per turn
The reason I shy away from doing so is because I don't know for sure, I can guess at what seems good but I will learn more about how to make a good thing by intentionally testing a weaker list