If you're starting up a game, you want a Black Lotus
Theres never been a Gruul Commander deck before this
Add in things like variants of cards, and this gets very complicated to communicate and understand
Leviathans are generally big and cost a lot of mana, but if you're aiming to cheat them into play with a Sin ETB or attack trigger, you might be able to build a pretty decent deck
WotC found Breach, especially with Mox Opal, made for a combo deck that was too fast, resilient, and non-interactive, even winning on turn one
Its not a bad thing as such, but it might leave some long-time MTG fans feeling a little turned off as they watch a world they adore becoming replete with characters that dont belong there