Mind Over Matter
Why does this card need to be banned? Did you read what it does?! If a blue deck drops this card, it's pretty much game over. With Azami, Lady of Scrolls, it's infinite draw. With Niv-Mizzet, the Firemind, everyone else is dead. With Temple Bell, you can dig for that Laboratory Maniac and force everyone to draw out (or until you win). Finally, with Tamiyo, the Moon Sage, it's infinite (insert combo here). This is just too powerful for a format that usually isn't decided by turn 6, like what this was designed for.
Sorin Markov/Magister Sphinx
Sway of the Stars and Biorhythm are both banned because they set everyone's life totals to a certain number. Why are these two cards (one of which is extremely easy to put into play) not banned then? Again, these cards were not designed with EDH in mind and they were meant to halve someone's life, not to one-quarter of it's original level. I partially want these cards banned because they aren't fun to play against, but it's mostly because they aren't designed for this format and as a result, their power level shot through the roof. Maybe another errata to say "halve target player's life".
Why should this be banned? Because Zedruu the Greathearted exists, as does Donate. If a player is getting ganged up on, all they have to go is give someone else this card and that player loses. Once again, it's not a card that's meant for this format since everyone already starts way above the threshold of this card.
Defense of the Heart
Once again, a card that was not designed for the format. Since EDH is a slower format, people tend to have bigger, more expensive creatures in their deck which means that this card gets a lot of value for its user. It's not difficult for an opponent to get 3 creatures either, which either means that your opponents won't play a third creature or they play one and trigger this card. Also, it's more repeatable in green than, say, Dramatic Entrance since it's a permanent.
Staff of Domination
This needs to be rebanned. It's a one-card combo machine. Plain and simple.
That's it. I'll be back to normal reviews soon.