I don't disagree (3000 hrs A320 family, 9000 hrs Boeing) ...BUT ... modern engines are much quiet(er) than older engines such as JT8D's. Ignoring for the moment the lack of pitch change with power on the FBW A320's, the glimpsing in your peripheral vision of thrust lever movement can be an early attention grabber and alert you to look at EPR's/N1's to see what is happening.
My first time on an MD-80 after years on the Boeings was, "How does this thing move without the engines running."
I enjoyed the 'bus and agree you had to pay attention to what it was doing but I thought that about the Lear 23 the first time I flew it.