should requirements for future Presidential candidates be strengthened and 'codified'...or at least agreed to...by all Political Parties?
The first consideration for most folks here, seems to be "Age". As someone who's a part of Trump and Biden's cohort, I feel I have sufficient "standing" to comment on the topic and suggest that a maximum age - just as a minimum age already exits - be stipulated. What that age would be is clearly up for debate. As further justification for the recommendation, military officers need to retire by a certain age, and in the civilian arena, I draw from personal experience, in that my Dad had to retire as a commercial airline pilot at age 60, in the interest of protecting the flying public, even though he was still an excellent pilot with tons of experience. The President is "Commander-in-Chief", so if Generals and Admirals have to step aside, so should their President when he/she reaches a prescribed age.
Next, in no particular order, might be Psychological Testing...in the case of our current President, it is becoming more and more believable that allegations of an 'Extreme Narcissism' personality disorder may be accurate. In justification of this requirement, I'm reflecting on the upcoming first deployment of my nephew as a Naval Aviator...to reach this point in his career, he first went through OCS and as part of the 'vetting' process, he had to pass a Navy administered psychological test. Had he been diagnosed with an extreme personality disorder I feel sure that he'd never have been admitted to OCS, much less flight training...so, if a junior officer needs to be tested like this, why not the one in command of all personnel?
Another would involve "Freedom for Outside Entanglements" (my term)...by this I mean 'Financial', 'Political' or 'Other' issues. The obvious "spur" toward this requirement is Trump's on-going effort to avoid releasing his tax returns, when all other Presidential candidates have willingly offered theirs. The potential for 'Conflict of Interest' and indebtedness to others is obvious and gravely consequential to the national interest, so complete financial disclosure is a key recommendation. As for 'Political' and 'Other' encumbrances, I'm reflecting back on the two secret "Q" clearances I needed to get earlier in my career...If someone is a candidate for the highest office in the land, then as a citizen, I want to know for sure that that person has been vetted fully...not sure that our current President would pass muster, especially after he gave a Top Secret clearance to his Son-in-Law, who had been previously rejected.
That should be enough to paint the "picture"...my overarching thought is that the job of President of the United States is the highest "Public Service" job there is...and if you don't want to be transparent and open to the people who's welfare and wellbeing you are tasked with...don't apply...find something else to do.