I may seem overly negative but my reason for delaying is that I think there's very little chance that a new manager bounce could meaningfully change the result in the upcoming matches, with the possible exception of Arsenal. I don't think the players have downed tools and obviously aside from different selections no replacements can come in till the window.
What could happen however is that the new manager bounce factor is wasted on games we can't win and in January when the schedule is kinder, the new guy will already have the loser tag to overcome. I also think if they're talking to people right now, they are more likely to get an agreement to come in after the christmas schedule so they're not hammering their own record before they've had a chance.
A guy coming in Jan 1st would have the window to bring a couple of loan/cheap signings in, a 10 day break before the winnable games start again to get some messages across and the chance to make the most of a new manager bounce.