I’m not familiar anymore with the old A320 but from my experience on the Neos and Sharklets ones I never saw sluggish behavior with the A/THR. Most of the times the large thrust variations I saw were due to aggressive pitch inputs by the PF. I always put thrust idle just before or during beginning of the flare at latest to avoid the engines spooling up unnecessarily.
Flying A/THR off is one of my favorite things while flying in good weather and it amazed me how the speed is so stable on A320.
I posted it earlier in another topic but if you look on that video a friend of mine made while I was flying raw data on A321 you can see how the speed is very stable and I barely moved the levers below 1000 feet.
Don’t know about you guys but personnaly I always fly at or above VAPP ( +5kt max ) while flying A/THR off to give me some margin. Don’t wanna take the risk of triggering a low speed protection.