There's one element to consider here that only got briefly waved at upthread:
How long should it take to get a character to a state where it's game-playable (answer: as close to zero as possible) vs
How long should it take to get a character completely fleshed out (answer: as long as it needs).
A character doesn't need to be completely fleshed out with background, flaws, etc. in order to be playable; those can be filled in as play goes along. But it does need all the mechanical bits in place, and that's where 5e - though better than 3e! - is still way too complex and time-consuming for my liking. Ideally, a 0e/Basic level of simplicity - choose race and-or class, roll your stats, figure out your spells if applicable, gear yourself up, and come up with a name and description such that you or the DM can narrate your appearance/name to the rest of the crew - is all it should otherwise take.
My benchmark for this is the answer to the following question: if someone's PC just died and that player needs to roll up a replacement NOW because there's not otherwise going to be an opportunity to introduce a new PC for maybe several sessions or more, how long of a break does everyone else have to take so we can get that new PC up and running?
If it's less than 10 minutes*, we're good. If it's in the 10-15 minute range*, I'll live with it. If it's longer than that, something's wrong with the char-gen system. And yes, my own system needs a long look as it's slowly become rather bloated over the years and char-gen takes way longer than it once did.......
* - assuming the player is reasonably fast at making decisions if-when they arise.