We had the first dolby A units in our studio in chicago. After several months of use none of us liked them and stopped using them. Most studios instead went to 30ips recording
The same was true for Dolby Surround films. They actually used Dolby-A on the L/R optical tracks on top of a second layer of Dolby-B or C (can't remember) for the decoded surround channel.
However! Based on my experience this was not on the encoding but the decoders. We used our own decoders instead of the Dolby-A cards and they had the best of both worlds. Low film noise and open/airy/immersive top end.
I suspect it should be possible today to build up an unofficial Dolby-A decoder digitally which is just as good.
( I worked for one of Dolby's competitors in film processor space)
Dolby Surround was based on fairly ham-handed steering for the sake of effects. Pow on the left! Bang on the right! That was the point. Movies were rollercoasters, and the Dolby Surround system was designed for this.
Fortunately, the sound on the tracks IS better than the decoders by far. Also, 70 mm films and the very rare magnetic 35 mm film used discrete channels. They sounded MUCH better.