Hi RAT.
For what it's worth, (and I have never flown moving A/THR levers), I find the Airbus easy to fly and interpret. If the speed bleeds away, I see it on the speed tape and trend arrow. I feel the reduction of energy by the change in pitch and sink, and see the pitch trim wheel moving. While this is happening I flick my eyes to the N1 or EPR gauges and expect to see the blue arc(s) appear that signifies a change of thrust command. Then I expect to see the N1 increase in response to the demand and I sense the speed increase through all the cues I just mentioned, including sound, as you say. I don't think that is any more work load than an aircraft with moving levers, and non moving levers do force me to keep up a good instrument scan which is a good thing.
So although the thrust levers are static, I am still able to assimilate the speed state of the aircraft. However, if the A/THR is being lazy or misbehaving, then it is harder to tweak than moving levers.
The danger is that by feeling the levers moving, some pilots assume that the A/THR is working. It usually is, but the levers are only the input, i.e. the demand to the engines, whereas pilots should be checking the output, i.e. the result of the demand, which in the case of the engines is the N1/EPR gauges. It appears anecdotally and from several speed related crashes that if the levers stop moving owing to a fault, or incorrect mode selection then this does not always get noticed by pilots, so a proper instrument scan is very important, as it always has been.
As we all should know and Centaurus's SIM demonstrated, not making a proper instrument scan can lead to disaster.