Yes, you could come up with a better form if the purpose of the form is to make divers aware of increased risks due to certain types of medical conditions.
But that is not the purpose of the form. The original purpose of the RSTC medical form, indeed the purpose of the creation of the entire RSTC, was to ward off US state and federal governmental regulation of the sport. The medical form was based on the existing commercial diver medical form so legislatures could be reassured that the standards were not being lowered so much that they would be ineffective. The one big change was to allow self-certification if none of the listed conditions were present. All commercial divers had to have it signed off by a physician.
Its current purpose is to keep insurers happy. Insurers are happy when they understand risks. The form has been around long enough that they are confident about the payout risk associated with it. A drastic change to the form would result in lower confidence in the payout risk and thus higher premiums to compensate for that risk. It would take several years until they had enough data from court cases to lower the risk premium they demand. The final premium would, of course, depend on whether the changes to the form made any difference to the expected average payout per policy.
That doesn't mean the form is set in stone, insurers won't object to changes in wording or even organizational improvements like recently occurred. But getting rid of the physician sign-off for any potentially qualifying medical issues would certainly result in a reappraisal of operator liability policies.