Blizzard have published a post explaining where the Dragonflight class design process will be at with the next Beta build, as they note that the focus will now be on tuning and bug fixes instead of design iteration on the class trees. However, there may also be more changes coming to the trees in the future if needed.
Class Design (Source)
We feel it would be useful to let everyone know where we are in the development of Dragonflight classes and talent design. With the next Beta/PTR build, we’re transitioning away from spending the majority of our time on the design iteration of the new talent trees, and we’re now primarily focused on fixing bugs and tuning the game. This includes balancing talent choices against each other and tuning the throughput of each class. We want to ensure that we release an expansion of the highest quality for this incredible community.
That being said, the new talent systems constitute a tremendous change to the game and represent a fundamental overhaul to how classes and specializations are customized by players. It is our expectation that we will be making adjustments based on your feedback throughout the expansion’s lifetime. We greatly appreciate all of your testing and feedback thus far, and we’re looking forward to delivering improvements to all of the talent trees in content updates throughout Dragonflight.