Lookleft: Thank you for your kind words however I have never flown the A321 only the A319/A320 variants. A rare moment of honesty not always evident on PPRUNE perhaps?!
However....... anecdotal evidence from talking to colleagues who have flown it suggests that the situation which you describe is much more common with the A321 than the smaller variants. Remember, the wing is essentially the same area but lifting a much higher weight. In addition the TE Flaps are different.
The most common advice would seem to be to ensure that there is a truly adequate margin between Vls and Vapp whilst using ATHR.
Your suggested technique is too vague since you would have no real idea of how much "extra" thrust would be delivered and the time taken for it to be delivered. The +5kts increment when using ATHR is to compensate for lag in ATHR response. If you were to use manual thrust no such padding is necessary and thrust response more immediate. Therefore the aircraft should be fully "flareable"(?) at Vapp provided that it is judged correctly.
In the situ. you describe, if the wind really is that light then I suspect that you are just flaring very slightly too late and/or too abruptly.
I have always found that whilst the A320 uses a normal flare the much shorter A319 simply needs a "check" prior to touchdown.