If a car has a naturally asperated petrol engine it wont have a lot of torque, or pulling power. A tradition torque converter automatic is quite an innefficient means of transferring the power to the road. So the combination of these two things can lead to the feeling that when you press the throttle down for a burst of acceleration nothing much happens except for a lot of extra noise!.

Is it significant?, depends on how much of a hurry you are in. If you have a car like this, you probably are not a 'press on' driver, so will be less bothered by it. But if you are a fast driver, and like to pass everyone going even slightly slower than you, i'd guess you'd find it very irritating.

My experience of petrol automatics, is that you have to be prepared to give them lots of welly in order to make good progress, but mostly to force the box to kickdown to get the revs up and the typical 16 valve engine up into its power range...no different to a gently driven manual, these modern naturally aspirated petrols need some revs or they are rather flat.

The problem with autos is that the 4 pot engines sound dreadful and strained when you get up the rev range, this is not such a problem with 6+ cylinders because they sound much nicer higher up the rev range.

Mercedes petrol engines could feel flat too, even the big 6's, but there comes a point in the timing when the upper range comes in, very similar in some ways to turbocharged engines, my ageing Merc gets to a certain point in the rev and speed range when it starts to feel like someone has just added a couple of cylinders, the higher and faster you go this increases, hence where many cars of its period would be running out of steam, those old Mercs are just getting stoked up...i have spoken to other Merc owners who describe exactly the same even with the V8's, probably other vehicles the same, i imagine BMW petrols would be..

Many people who have had turbo Diesels have become used to vehicles pulling strongly from around 1500 rpm and no point in going above 3000rpm, and going back to modern relatively small non turbo petrols they don't really come on stream till you are doing about 2500rpm, or as with Honda VTEC's till you get up to about 4000 rpm when the second valve train comes in.

I wonder if people now going back to petrol last had a petrol with 8 valves, usually less powerful in bhp form, but tended to be more tractable with higher torque from lower revs than the 16 valves units.