I wouldnt call it over-promising or under-delivering ...
I would call it realizing their misstake, and changing their design
The difference is communication; if they change their mind about a feature that was earlier stated to be happening, and they *don't* tell the testers that it is no longer happening, then
Yes, it is over-promising and under-delivering. If they
Tell us that this is an element that they've realised they can't achieve satisfactorily and are redirecting their resources, then that would be them changing design direction. Communication makes the difference here, and as of yet, the last word we've had from Larian is that the custom PC will be fully voiced... and if they have decided not to do that, but don't tell us so before release, then it is a broken promise.
I don't WANT a fully voiced PC - especially not if our only voice options for barks is going to remain two different flavours of modern brittish accents. I'd MUCH rather they give us a more diverse set of base voice templates for our in-game barks, to cover a broad variety of voice types... and if they aren't giving the pc full voice acting, confirm that this is the case now!