Continuing their glacial pace.
The "glacial pace" seems to really work from a business perspective. You want them to move away from a pattern that seems to make good business sense?
I mean, we are talking about settings for a game that is itself a rehash - yet another edition of D&D. It appears to be a stupendously successful rehash, however.
What I don't understand is how some fans can be happy with, and actively defend, how they sell the same thing more than once.
1) Mechanics have changed. Wanting setting mechanics that are designed to work with the current edition mechanics should not be difficult to understand.
2) Given what we have come to think about the amazingly solid sales of the core books, it is hard to think that they haven't been adding a whole lot of players in recent years - players who haven't been exposed to the setting. To them, this is not really a rehash. It shouldn't be hard to understand giving new players a thing that this new to them.
3) Again, I think there's a good business perspective argument to be made here. Updating old, but proven, properties is less risky than new material. Though I personally don't care about Eberron itself, the fact that it has a draw seems quite solid. This should also not be difficult to understand.
The idea they would give us a whole new setting out of nowhere simply isn't the business WotC is in any longer.
They haven't really been in that business... really since the end of 2e, two decades ago in the mid 1990s.
The patterns of the period where they put out frequent new settings were a financial ruin for TSR. Compared to how this "glacial pace" seems to be serving them well. You really want to argue with success?