I'm in favor of it. There is no valid reason why, if a pilot is fit and medically qualified, he or she cannot operate as captain above age 65.
This is very much a matter of get-out-of-my-seat, old man, I-want-your-job.
Those who think their career progress is stymied by those above them failing to retire seem to be quite willing to ignore the premise of seniority, when it suits them. Seniority is everything, they say, until they want what someone more senior has: a job. Get out of my way, old man, I want your job. You were here longer, you served longer, you have more experience, and you've earned your position more than I, yet you must go so that I may get what I'm entitled to: your job. Make room for me, old man, because I'm entitled.
No, if the captain is able to do his job, then he is able to do his job.
Will it do much, if anything, to alter the state of the imaginary "pilot shortage?" No. No more than dumbing down or reducing the qualifications for entry level pilots with their ATP. It may alter timing slightly, but not the numbers.
I was in cockpits with flight engineers when the age was raised from 60 to 65, and I flew with pilots who retired from a pilot seat to the FE seat at age 60, then moved back to the left seat when the age was raised to 65. The same loud objections and whining echoed off the heavens when the age was raised to 65, and we saw no elevated safety issues connected to the change. Just entitled sniveling curtain climbers who felt that they were owed something by those above them getting out of their way. The same get-out-of-my-way, old man, I-want-your-job entitlement then. I saw those same captains reach 65 and move back to the FE seat. The tired argument that they'd be sick of flying and sick of earning a living and worn out at age 60 didn't hold true at age 65. They would have been quite capable of continuing as captains, should the retirement age have been 67.
I got a union communique recently urging me to protest the drive to age 67. I disagree. I'm for it. Wholeheartedly. I was for raising the age to 65, and I'm for raising it to 67.