One of my old Magic groups used to have a
multiplayer rule where a player could gain a
designation in the fashion of the monarch. In
our case, though, it was awarded to the player
who currently had the lowest life total, and
that player couldn't be attacked as long as
there were more than two players left in the
game. Obviously that's not quite as big an
advantage as getting to draw an extra card, like
Conspiracy: Take the Crown's monarch - but
there's no better way to get Magic players as a
group to adopt something than to let them draw
extra cards.
I think it's a little funny that Marchesa makes
you become the monarch, when in the storyline
she's one who's the queen of Paliano. I didn't
think she was really the type to share, to be
quite honest. However, everything about her is
designed to seize the crown and hold the crown.
Remember that you become the monarch when your
creature damages the monarch, and a lot of
people will find being the monarch hollow when
they had to us a Wall of Frost or a dragon to
block a 1/1 token with deathtouch. And if that
avenue isn't working for some reason, Marchesa's
also in the right colors for flickering,
reanimation, and other such shenanigans that
make it entirely unnecessary.
Marchesa, having taken the crown from the
long-undead ruler of Paliano, has changed a bit,
swapping out her colors (from Grixis to Mardu),
picking up combat-relevant abilities (deathtouch
and haste, replacing the old one's
dethrone) and…well, adding a crown. The
new ‘Monarch’ mechanic gives you an additional
card at the end of turn, with the caveat that
someone can become monarch by dealing combat
damage to the reigning monarch. Yes, this works
in Legacy and Vintage (not that you’d probably
play Queen Marchesa in those formats; Mardu is a
fairly weak color combination in Legacy).
And if someone takes the crown from you,
Marchesa churns out tokens to try and get it
back. Them being disposable assassin tokens
makes them even more difficult to handle safely
and efficiently, and throwing enough of them out
will make it all the more likely that you can
get one in there to get the crown back.
Queen Marchesa is a massive bomb in Limited, but
I don't think she can get there in Legacy or
Vintage; she's a bit too “fair" and slow for the
high-powered Legacy and Vintage tables. She’d
actually be good in Modern (and absurd in
Standard), but Conspiracy isn’t Modern-legal.