The problem with raising the age is that age demographics are generally disparate.

One critique often given of SS is that the poor pay for it all their lives... and yet their average life expectancy is as such to never see retirement.
But on the other hand middle class people have constantly growing life expectancy.

My thought is this:
Raise the retirement age... but lower and make more accessible the early retirement age... and then make the penalty for early retirement greater... like down to a minimal base pay.
This will still be appealing to low income workers (with a lower life expectancy and with low-skill jobs where the are easily replaced and where they open up positions available to just about anyone) and unappealing to most medium-to-high income workers, who will expect to live longer and who have jobs that require more skill and promise greater benefit through continued work to retirement age.

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"Man lives in the sunlit world of that which he believes to be reality. But unseen by most is an underworld, a place that is just as real... but not as brightly lit... A DARK SIDE!"
-opening from Tales From the Darkside