I think it will depend on how many DLCs they make tho. Replaying a big RPG 1-2 times is pretty common in the fanbase, and it makes sense to wait for the main story DLC to do it. But if they suddenly would have all 6 DLC purely for the main story, I doubt majority of people would want to replay the whole game that many times.
I don't think many players would replay the game just for the dlc, but if the game was good I will likely replay it in a couple of years and a bunch of dlcs is a bonus.
Either way, I personally prefer dlcs which either continue the main campaign or expand it, but you can play them by loading the final save. For some reason, Owlcats didn't have such an option in their survey despite that it is the most common & obvious way to embed dlcs. I'm 100% sure the majority of players would prefer this instead of replaying.
It's the hardest option to do tho, and often still the one that fails to satisfy players. People think they want that, but they really want a proper sequel, continuation of the story, which a short DLC can't deliver. You end up with a random disjointed adventure, using some shitty excuse and usually ignoring most possible endings, to bring your characters back for a couple of hours and make them run another bloated high level dungeon with a villain you won't care about. WotR had one DLC like that, and it was received worse than the even the low-level side campaign one.
The proper way to do it, is to make a full size expansion, like Awakening for Dragon Age, but this requires as much effort as 6+ smaller DLCs, while having the price of max 2-3, so 99% of the devs don't want to do this. Also still there is no guarantee players will like it (Codex mostly hates Throne of Bhaal, for example), since it has a lot of same problems as the post-game small DLCs, creating satisfying and balanced high level content is very hard, and continuing the story in a satisfying way is even harder, especially when you didn't plan for the expansion and the game has a proper, definitive ending with ending slides and shit.