The problem with moving thrust levers to idle too early is that the auto-throttle has got no authority to exceed the thrust lever position, ie any decay in speed has no correction because the thrust levers are already at idle. Please note my careful choice of words "too early". Without AT authority, no alpha floor, no windshear warning and an early thrust lever closure, any gust in TW sets you up for a hard landing. As I said, I have experienced this.
Although the FCOM doesn't mention it, I have seen little to no AT reaction to speed decay at low RA. The FCOM says it will maintain VAPP as a minimum as long as AT has authority, but I believe, and have noticed this in actual flights, that below a certain RA that doesn't happen. It's like the undocumented behaviour of the stall warning not announcing below a certain speed that was only discovered by Airbus pilots after the AF crash. There's a lot going on that's not in the FCOM.
Having said all that, it is very difficult to keep an eye on airspeed while simultaneously flaring and moving thrust levers to idle. I try to do so but it is high workload. If in doubt about gusty conditions I add a few knots; if crosswind exceeds 15 knots I add a few knots there as well. In my operations I am never constrained by runway length so I accept the additional touchdown speed.
For the pedants: a few knots.
For non-pedants: please share your techniques if you think there is a better way.