My son, up to EA BG3 completely ignorant of DnD, was absolutely baffled, bewildered and bemused by the character creation process.
In spite of all the tips and tutorials The Oaths - and other sub-class choices at Tavgenesis - were yet another complicated and confusing matter.
Hence IMO moving the choice of Oath to later would "lessen the pain" for newbies.
There are two things here : 5E's fundamental complexity and BG3's onboarding process.
Regarding D&D 5E's fundamental complexity, and by complexity here I mostly mean number of options, one thing that 5E was doing fairly well, was to postpone some choices to level 2 or 3 (this was, essentially, 5E's way of making onboarding easier for players who prefer a lighter introduction). In particular some Subclass choices. For some Classes (namely, Cleric, Sorcerer, Warlock), given the canonical lore/flavour, it made more sense to choose the Subclass at level 1, but otherwise, Subclasses were chosen at level 3, except for two that happened at level 2.
Now, given 5E overall simplicity, for gamers used to learning rules or players who've learned D&D 5E and have become familiar with it, the early-game ultra simplicity may have been a bit too much. To the point that many games/campaigns would start at level 3, because that's where your character really started to become what you wanted. My vague understanding of D&D 5.5 (or rather One D&D, as its currently named), is that there might be a bit more complexity at character creation (I think that more Subclasses will be chosen at level 3 but you'll get feats from level 1, and thus access to a menu of options).
Regarding BG3's onboarding process, BG3 is rather bad at teaching players the rules. Tooltips have become a bit better in general. But the character creation screen is still horrible.
Notably, it fails to show how your character will evolve, and what the future implications of your current choices are.
It also don't present the choices to make in a simple order. You often have to go back and forth between tabs (skills is a particular bad example, since you choose 2 in the Origin tab, and some more in the Skills tab, and the presentation in that latter tab really isn't great).
