I'll close this ticket as it doesn't seem pressing anymore. The Fedora change proposal that actually got approved wraps tuned in a p-p-d compatible wrapper, and as @davidre mentioned above, regular p-p-d is no longer archived. GNOME has enough clout to ensure that whichever power profile solution we get in the future, it'll likely get abstracted to "powersave"/"balanced"/"performance" on a level lower than the desktop environment itself.
Although I guess it could be nice to replace vendor-specific profile selection, e.g. like Tuxedo Control Center offers, with a properly integrated mechanism.
But perhaps this kind of project should take another angle anyway, or we can reopen this task if/when we consider it important enough to invest actual time & effort into it.