I suspect the character creation options will be barebones. I'm sure there will be a variety, but it will not be particularly comprehensive and will be "good enough" (meaning it won't please anybody, but will be enough to play without being entirely disappointing). Larian seems pretty set on massively pushing players to use the pregen characters given the amount of work put into them having involved backstory included in the narrative. I get the effort there and don't begrudge them that honestly, it's almost essential given everyone being voiced (a problem that does not exist with silent protags, which I've always preferred).
The major perceivable downside at this time (for me anyway) is that before you even begin play, the experience is already diminished if you create your own character from scratch (which with D&D, is entirely the damn point) when compared to the experience you'll see with a pregen character. You can fashion an incredibly compelling motivation and narrative agency in a character created from scratch (see Baldur's Gate 1 and 2 among the many that exist). Pregens give you more freedom on the creative side to add voiced dialogue throughout, obviously...but the character isn't yours. It's Larian's.
It won't stop me from playing it of course, but I'll certainly never use one of the pregens (as party NPCs, sure, but I will never choose to play as one). I would much rather have seen/heard of Larian putting all that effort into creating compelling options for player created characters...but what's done is done and I'm sure it'll be good enough.
