I don't see a problem with Xander when compared to other commanders. As others have stated, 7CMC is prohibitive enough given that it requires 3 separate colors to cast. This makes it harder to cast than
Toxrill, the Corrosive which I would argued should be banned first. Next, that the ETB is not consistently repeatable when compared to say
Tergrid, God of Fright or Tergrid's Lantern. As others have said, removal is necessary; the dies trigger does not go off with
Path to Exile,
Swords to Plowshares, or bounce effects like
Brazen Borrower. In, closing I would be more scared of Toxrill, Tergrid,
Sheoldred, Whispering One,
Kroxa, Titan of Death's Hunger,
Jin-Gitaxias, Core Augur in the command zone, additionally
Archfiend of Depravity,
Nicol Bolas,
Nicol Bolas, the Ravager are oppressive.
Xander is a reason I would like to see "Banned as a Commander" return.
An ETB trigger. An attack trigger. A death trigger. That all blow up hands, libraries, and permanents on the field.
Seems to be on a similar axis to Leovold. Leovold, Emissary of Trest was banned because he shut down opponents while being a draw engine; and being repeatable from the command zone.
Xander does not provide any direct benefit to the controller. But shuts down opponents on multiple fronts. Passively. No hoops to jump through. Just cast him OR swing with him OR have him die. Any of those can completely wreck an opponent's board state. Loop any of those actions and now you've shut down the board. And it's repeatable from the command zone.
As one of the 99 I think Xander would be a decent combo/control piece.
As the leader of the deck, I would also like to see Xander banned. I see a lot of discussion on line about Xander. I am really hoping that Xander prompts the return of "Banned as Commander".
P.S. Until that time, I do plan to build Xander to see how bonkers he really is. I'm hoping we can get a Xander vs Xander vs Xander vs Xander at my LGS.