My understanding is that motor coordination is a mostly separate issue from attention regulation and task completion, so it would make sense that a stimulant would address focus and impulsivity (as well as suicidality and criminality by proxy of those) but not clumsiness. Also, one can have ADHD without being clumsy, but being clumsy alone does not quality for ADHD.
I could be completely wrong, but hopefully that explains my take better. I'd be happy for someone to correct me.
Not a fan of "clumsy" reminds me too much of "lazy"...
Anyway, back on topic: I wonder if there are 2 specific neurodivergencies going on that got wrapped up into ADHD, but only one actually has to do with executive functioning and serotonin (the 70% that get helped by amphetamines) while the other has to do with sensory and body awareness stuff.
If they have high enough co-morbidity or are weirdly co-morbid so that we never see the body stuff unless the person has ADHD we might have a difficult time seeing them as 2 different things that might be close by brain-location or gene-expression or something.
There are murmurs around me about celiac disease being related to ADHD and autism so that would be another thing in the neurodivergent body area
I could be completely wrong, but hopefully that explains my take better. I'd be happy for someone to correct me.