As Kantr said, there's no day 1 dlc...
But I'm more concerned about the bolded part... How would you know that there is "less" new content? The story is either complete or it isn't... The addition of Legacy and Mark of the Assassin DLCs didn't mean that DA2 was made with the excuse that there was "less new content" in it...
Those are completely different (I hope). Legacy and Assassin were made after DA:2 (I hope) and were added on. That's fine. Whatever was supposed to be added to DA2, was made before or along with Inquisition. As far as "the story is complete or it isn't", all that means is that there is a beginning and an end. There could always be more in the middle. Also, like most of these DLCs, it need not be related to the main plot, but it's still interesting content.
As we've discussed in other contexts, they have limited development time and resources, so working on one thing limits your ability to do something else. Now if it was already pretty much done, it might not take that long.
As to how I would know, it's possible I never would know, but that wouldn't mean it didn't happen. I brought it up as a possibility, but didn't claim it happened. But we've seen it before with other games. Granted, most examples I've heard were for smaller developers.