Update from PR comments

Author: pwittrock

contributors/design-proposals/sig-cli/kubectl_apply_getsetdiff_last_applied_config.md

@@ -26,23 +26,27 @@ manner.
 ## Use Cases
 
 1. As a user, I want to be able to diff the last-applied-configuration
-against the current local configuration to see which changes the command is seeing
+   against the current local configuration to see which changes the command is seeing
 2. As a user, I want to remove fields from being managed by the local
-object configuration by removing them from the local object configuration
-and setting the last-applied-configuration to match.
-3. As a user, I want to be able to view the the base
-last-applied-configuration that will be used to merge changes
+   object configuration by removing them from the local object configuration
+   and setting the last-applied-configuration to match.
+3. As a user, I want to be able to view the last-applied-configuration
+   on the live object that will be used to calculate the diff patch
+   to update the live object from the configuration file.
 
 ## Naming and Format possibilities
 
 ### Naming
 
 1. last-applied
-2. last-config
-3. last-applied-config
-4. last-configuration
-5. last-applied-configuration
-6. last
+
+Rejected alternatives:
+
+2. ~~last-config~~
+3. ~~last-applied-config~~
+4. ~~last-configuration~~
+5. ~~last-applied-configuration~~
+6. ~~last~~
 
 ### Formats
 
@@ -98,24 +102,32 @@ Same as above, but in json
 
 ## diff last-applied
 
-Porcelain command that retrieves the object and displays a diff against the local configuration
+Porcelain command that retrieves the object and displays a diff against
+the local configuration
 
 1. Diff the last-applied
 
 ```sh
 kubectl apply diff last-applied -f deployment_nginx.yaml
 ```
 
-Opens up a 2-way diff in the default diff viewer.  last-applied is old, local configuration is new.
+Opens up a 2-way diff in the default diff viewer.  This should
+follow the same semantics as `git diff`.  It should accept either a
+flag `--diff-viewer=meld` or check the environment variable
+`KUBECTL_EXTERNAL_DIFF=meld`.  If neither is specified, the `diff`
+command should be used.
+
 This is meant to show the user what they changed in the configuration,
 since it was last applied, but not show what has changed in the server.
 
+The supported output formats should be `yaml` and `json`, as specified
+by the `-o` flag.
+
 A future goal is to provide a 3-way diff with `kubectl apply diff -f deployment_nginx.yaml`.
 Together these tools would give the user the ability to see what is going
 on and compare changes made to the configuration file vs other
 changes made to the server independent of the configuration file:
 
-
 ## set last-applied
 
 Porcelain command that sets the last-applied-config annotation to as