There are no clear weaknesses, and whatever weaknesses Mardu seems to have can be alleviated by shifting roles while sideboarding
Magnanimous Magistrate FromTheShire: This is interesting as a sort of workaround reanimation thing, and in a deck with a bunch of blink and reanimation so you're not paying the heavy casting cost I could see this being part of an interesting loop
That 3rd toughness makes a pretty huge difference in making the cards baseline a lot less miserable A two mana 2/3 with defender isnt great, but in a defensive deck it isnt unplayable, but the ceiling on this card just isnt very high, and neither is the floor
If a creature has protection from a particular [quality] like white or dragons, you cannot use that something to block the creature
Plus, its hard to interact with these effects, especially in best-of-one matches, so it snowballs very quickly
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