I heard some commentators rumbling over the possibilities, and I think it would be a terrible mistake for the DNC if they did this.

The decision was made prior to any of the primaries to strip these states of their Democratic delegates because they moved up their primary election dates against the written policy of the DNC. Whether that was fair or unfair is certainly debatable, but the Party set its rules, and the candidates understood this and ran their campaigns accordingly.

To change the rules of the game in the middle of the game is patently unfair, especially if the reason for the change is because the race is rather tight. By suddenly giving the right to these states to hold second primaries with a reinstatement of delegates gives the appearance that the DNC is looking to bolster the prospects of Clinton. Florida and Michigan knew they were risking their eligibility to seat delegates when they moved their primaries to a date earlier tha 2/5.