...include a survey for players at the start of the game asking them about some of the major choices they made in the first two BG games...
Maybe I'm wrong, but I suspect there aren't more than a few dozen players who would get anything out of this.
Those games were a long time ago. Plenty of people either never played them or completely forgot their major decisions. I doubt there are many players left who still feel connected to their old characters outside of some passing nostalgia.