There could be a text field near the milestone icon, and in there would be a place to put a one word tag/keyword describing the milestone, and also there would be an option to select a color for this keyword.
This keyword would than be visible for the milestone in the table view the same way custom fields are. Every task blocking the milestone should have this keyword visible in the table view too.
The same problem is actually adressed by workaround in this tutorial video: How To Do Scrum Project Management in Asana (in 2022) - YouTube
Marquis, the author of the video, created custom fields with values [story1, story2, story3] to make the dependency between tasks and milestones more visible.
It would be nice to have an option to sort tasks in the table view by the milestone keyword.
It would also be nice to have a dropdown list option with milestone keywords in given project to simplify a process of creating blocking dependencies.