If anyone is overselling it, it is Firaxis. They've made the leaders with their unique abilities and agendas prominent in their marketing from the very beginning."distinctive".
I think you're overselling how the AI acts. That aside, it's quite easy to give anyone a 'distinctive' personality. All it takes is exaggerating certain traits. Like how Victoria comes off as a brat when she's angry.
Also, your second point feels rather inane. By that reasoning we should just do away with leaders altogether and just use country banners.
Country banners would not seem to offer much in the way of personality.
She is most certainly not recognisable. Case in point, look at how many people on this forum alone thought her concept art was Aethelflaed.
An occupational hazard for representations of medieval leaders, I should think, since no accurate likeness generally exists. Eleanor may not be as well-known as Elizabeth but few medieval leaders are. For the period, I think her name recognition, at least in the UK, is pretty decent.