I would play a custom character and I would like to see the option of choosing one "origin"/back story like in DA:O so I have quests and story arcs related to that. Having the game world react to the custom character story is interesting.
For me, Origin characters are fine as companions. But I won't play as them. If it goes like DOS, I tried two, get bored and stopped playing. DOS2 was obviously meant to play as an origin character since they have a lot more content than custom character, yet, it wasn't engaging to me.
As for the numbers, if with much less content than "origin characters" people still choose to play custom, then what people would have choose if custom characters would have had the same amount of quests, dialogs related to the background, etc? And what was the number break among the origins? Because if some origins were played by less than 10% of players, then maybe investing so heavily in having so many origins instead of just companions might not be as logical as investing in doing custom characters right. Or more companions.
In DOS2 people choose between a custom character who only have the main plot and an origin character that they could customize, that offered then main plot+ personal quest. Not even choices.
So maybe, they shoudl offer small stories to pick from at character creation and that are related to quest and world interaction. The custom character story that exist in my head doesn't provide interaction with the game world and I like the choices I made on character creation acknowledged. Is nice to have options as a wizard (I suspect they are there for Gale XD). IT would be even nicer to have scenes, dialogs and a personal quest for a custom character.