Automatic milestone types are great to keep track of changing values on critical fields like Customer Success Manager, Sales Account Owner, etc.
This works lovely if you are changing the value from one to another. For example, if you update the CSM from Nathan to Rachel, Gainsight will create a milestone with subject/notes: CSM changed from Nathan to Rachel.
However if you just remove a value, say update the CSM from Nathan to NULL, Gainsight will create a milestone with subject/notes: CSM has been removed. You lose the benefit of the historical value that got changed!
Request would be for when values are removed to still display the old value for reference in the automatic milestone. For example, Nathan removed as CSM.