Sometimes an opponents sitting at two 2, or if your Commander was killed two or more times in the game already, choose to send it to the graveyard, then return it to your hand with Kolaghan's Command to avoid paying commander tax
You can't change modes, though you can change targets for any copied modes that involve targeting
I think its also the trigger that Ive forgotten as often as Ive remembered
If you have a decent board-state, Ajani can really give you an advantage, but he doesn't add anything to the board on his own, and takes some time to give you that advantage
In each color, theres a card that says if you control a commander, you may cast this spell without paying its mana cost. As you might imagine, theyre all kind of bonkers
Arixmethes, Slumbering Isle You cant put legendary lands in the command zone, but Arixmethes, Slumbering Isle isnt too far off