Most legendary creatures are bad as Commanders, but hey, if you want to have Cho-Manno, Revolutionary as your leader, Im not stopping you
NEW CARDS
Finally, we've got Rings of Brighthearth , which can double any activated ability
Though a controversial move in Commander, infinite turns are almost always a guaranteed win as you'll just keep playing through your deck unimpeded until you have your finishing moves
Some examples of this are cards like Alms of the Vein or Alchemist's Greeting, which arent really good cards for their original costs
Turn 4 - Drop another land, use your five mana to cast two Auras on this that pump its power and toughness, like Blanchwood Armor that might be +3/+3 and grow and Arachnoform that gives +2/+2 and you now have a 17/15 trample vigilance beater and swing and might win in a few hits