Disclaimer: this is my personal opinion. People have their own views on what the value of a game is, and that's okay.
1. I'm not rushing to buy in early, or on release date. Zos showed that they're not going to offer anything special to those of us who pre-order. What would a good preorder bonus be to me? Maybe 1,500 crowns, or a 15 pack of crown crates. One crate is a no...ha.
2. I won't buy at all if any one major segment of the new content is something I won't want to play. I bought Morrowind thinking I'd love Battlegrounds, but I knew I hated non-CP content. From now on, ZERO LOYALTY when Zos forces a mechanism I don't want to play under. It's their game, no harm no foul if they develop content I don't like. But no more paying to support the game, thinking that there will be a quick expansion of the content. (Based on the way they described Battlegrounds, it seemed like there would be added functionality quickly, including CP play and the ability to choose the game. Now that I see it will be 6+ months, no ordering at release under an assumption they'll add features to Jew content quickly).
3. I won't be buying chapters until they're on sale. I paid $60 in June for the collectors edition, and by August it's on sale for $40. I thought Morrowind would be so cool I'd want to spend the summer playing, but in all honesty if I were starting today at 33% cheaper I'd be happier. Because the pre-order bonuses are lame, no harm in waiting to hear what people think before buying.
4. For that matter, I'm not sure what will make chapters worth real world money at all. For me the value of Morrowind was mostly the new class. The area wasn't much more than any of their DLCs...it's cool, but it wasn't $40 vs 1500 crowns cool. I can't imagine that next year's chapter will introduce a new class. Somthere has to be something big on the table to make it stand out above a regular dlc.
5. Some of the above MIGHT change if the next chapter is Elesweyr and not Black Marsh, because honestly Argonians transmit salmonella ifmyou don't wash your hands constantly.