If you aren’t using a custom rotation the default should work better as it’s got much more data available than what you can get in the old gearing strategy.
I’ve got no idea how long until they work again, a brief forum search found this post indicating that there is extra work needed for them to work again.
Next reset Mythic opens for the new raid, with this reset it would be very unusual if there weren’t some balance changes gathered from the data Blizzard uses from the Heroic runs this reset.
The AMR team will need to adjust things for those changes so the main purpose of the site works well for 99+% of their users.
I’m sure the AMR team would be very interested in what you think the custom gearing strategy did better than the adaptive one, if it’s a significant improvement I’m sure they’d want to incorporate it into the defaults.