This expansion has apparently been in development from the beginning. It was already planned. And had they met their original release date, it would have been released right around the time frame when they said they wanted to release their first DLC, (three months after launch...).The way I see it, Ark's original release has been delayed only because the studio found that it wanted to do more than it originally planned and ultimately deliver a better product. You could maybe argue that's not the best way to run the development process, but I am continually awed by what this team can and is putting together. I will happily buy the DLC, enjoy it to no end, and continue to support this amazing team. I look forward to full launch with even greater anticipation.
Also, with regards to the concerns over adding fantasy creatures to ARK, I welcome the blend, and for those that want the DLC maps to remain separate, I'm sure that sooner or later there will be Vanilla Servers for various DLC that don't allow creatures from other ARKS.