My answer would be that for me it would be something some of my PCs would take but not for power.Let me put this a different way.
If there were a feat, and the ONLY thing it did were grant Expertise in one skill, would that feat be overpowered? Would a lot of people take it?
Problem is that at low level it's up against not only the ASI on prime abilities (which many prioritize) but also the feats which add new abilities, open new doors (which I prioritize) and by the tier 3 timeframe skills are now longer as crucial that burning a feat for +5ish in one skill to be worth it.
But you could likely put "clerics turn undead once not twice" into a feat and see the same thing.
Now, if "reliable talent one skill" were a feat, that's imo a lot more appealing than expertise.