A possibly better idea is to push back on tzdb's choice to unify
these zones. Don't know if they'd listen, but we could try. The
UCT symlink hasn't been out there so long that it's got much inertia.
One oddity; AIX had a preference for CUT with fallbacks to CUT0 and UCT back when we had AIX boxes (5.2 or 5.3, if my memory still works on this).
We wound up setting PGTZ explicitly to UTC to overrule any such fighting between time zones.
There may therefore be some older history (and some sort of inertia) in AIX land than meets the eye elsewhere.
That doesn't prevent it from being a good idea to talk to tzdb maintainers, of course.