A question of fairness.

[Liminal Syzygy]

I agree that you should have the option to change your feats if the rules are changed mid-campaign.

 

[reapersaurus]

However, it is his game

No, it is THEIR game.

The DM is the one most responsible for organizing it and has creative control.

He should NOT be jerking around the players by changing rules mid-stride and then not having the sense of decency to allow for players to change.

P.S. He sounds pretty weak if a couple weak magic items are threatening his game-control.