Pretty much. The rule for Phasing is pretty simple:
1.) Things with Phasing you control in play at the start of your turn phase out.
2.) Anything you control that is phased out at the start of your turn phases in.
Things that are Phased out can't suddenly lose Phasing and stay gone forever.
Exception: Permanents that are indirectly phased out due to being attached to a permanent that is phased out will be lost to phase land essentially forever if the permanent they were attached to was a token (which ceases to exist when it's phased out, despite this no longer being a zone change).
This is the one mechanism that remains to remove an opponent's commander essentially without hope of recovery. (
Imprisoned in the Moon or one of a few other effects into
Liquimetal Coating or
Mycosynth Lattice;
Bludgeon Brawl on the field,
Grip of Phyresis if you have + toughness to your board or
Magnetic Theft to a token, then peg the token with
Reality Ripple)
EDIT: As best as I can figure it, the best way to do this repeatedly starts with, of course, the Liquimetal (or Mycosynth?) and Bludgeon Brawl. Use
Soul Sculptor to make the commander a noncreature. Either have Magnetic Theft on a stick or kill
Aura Thief (loopable many ways as a creature. Flicker
Reveillark?) and attach the commander to a token. What token? The token of
Crystal Golem you made with
Mimic Vat,
Soul Foundry,
Prototype Portal,
Mechanized Production, or so on to kill two birds with one stone. End of turn comes around and Crystal Golem token senses its destiny and takes the offending commander where none may follow.