Cards like The Queen, Commanding Presence and Gaston, Intellectual Powerhouse are about as tricky as things get, but they simply do what they say on the card and get players used to the powerful (at least in my eyes) shift mechanic, which is a cost reduction method
Not only mention some trial and error as you test out new tactics and card combinations
(Four or more depending on how you count Ardenn, Intrepid Archaeologist and/or Rograkh, Son of Rohgahh!) Its funny that it took 16 years to get a Boros Equipment commander, and then WotC proceeded to turn on the firehose
There are are lots of different ways to play with a Cube
"Dragon Master Knight", "Dragon Master Magia", "Cyberdark End Dragon", "Five-Headed Dragon", and "Phantasmal Sacred Beasts of Chaos" are tied with the highest ATK of all Fusion Monsters, with 5000 ATK each
This can make it a useful card for time rules