FGD, amos2, BOAC
You are correct in your personal assessment of the rotary dial (angular motion) versus the speed tape (straight motion).
I have not checked with NASA but to say it short: The human eye detects motion much better than still objects. The human eye also have an affinity to remember angular displacements better than straight displacements. That is, it is easier to remember the position of a rotary display than the position of a speed tape.
The longer story:
What is more alarming in an aviation context is that the eye will have problems detecting digits on a moving speed tape - because the movement "silences" the underlying information. That is, a pilot can see the speed tape move, but it takes a concious effort to understand what it means since the movement itself blocks the information on the tape. One study found that the movement even could block colour information - dangerous when approaching stall speed!
We are designed to detect movement first and foremost. A heritage from our nomad ancestors. Movements were often dangerous (predators etc). Digits came much much later and we need extensive schooling to understand their abstract meaning.
I hope that some intelligent airplane designer puts back the rotary speed indicator. Not everything is better with a glass window.
You can have a bunch of references here:
Effects of stationary and moving textured backgrounds on the visuo-oculo-manual tracking in humans
Visual perception of biological motion and a model for its analysis - Springer
(discusses human movements but they are in fact all angular - rotary - movements in some way)
Is it just motion that silences awareness of other vis... [J Vis. 2013] - PubMed - NCBI
Spatial and temporal selectivity of the human motion detection system