Shemeska
Adventurer
I agree with this.
Though I am curious what the 5E view for Tieflings will be since the 4E PHB style Tieflings were a departure from the style of Tieflings which had come before.
If it were me, I'd simply say the 4E style Tieflings (and the ones which would be in the PHB) were from a specific bloodline tied to the specific pact made by that bloodline many generations ago; hence the more uniform appearance to that style of Tiefling. That allows to have both styles while acknowledging that they aren't the same thing -despite sharing a common name. "Tiefling" could be the broad category; more 'scientific' names would refer to specific types of Tieflings.
Absolutely. Well prior to 4e there were already specific true-breeding lines of tieflings such as FR's fey'ri (a line of gold elf / demon-blooded tieflings), and if we need to preserve the 4e tiefling as an option in print, that would seem like the intelligent way to go. But the default should probably go back to the 2e/3e classic tiefling with their wild crazy variety of heritage, origin, and descent from any fiend at all.