I have noticed that the A320 flies very bad in tail wind . A321 flies much better in that condition and is more stable.
As for the 320 with a Tail wind adding few knots to your Vapp will help the aircraft fly better , you would have more lift and better control for the flare .
In Leaving the Vapp "incorrected " and retarding at the Retard call will definitely result in a positive or sometimes a high g landing.
Now If you see that the aircraft starts sinking and that controls are sluggish and not really responsive . The only way to recover is :
Disconnect the Auto thrust in the "wrong way " . I mean Leave the Thrust lever in Climb and Disconnect the Auto-trust using the instinctive red button and then immediately Retard.
By doing so , Thrust would start to increase on its way to Climb thrust and stop the pitch down moment , then immediately followed by retard .
So these 2 actions are almost done in the same time: disconnect Auto thrust and Retard "
Excuse me Captain "fly indigo" but retarding when your aircraft starts sinking is poor airmanship and this could lead to a tail strike and high G landings
What I have just described above , is not an airbus procedure but common sense is not written in the FCOM.
A 737 pilot would simply increase the thrust when his aircraft starts sinking during the flare so airbus pilots should not forget basic jet flying skills.