Permanent solution to slow open/save dialog?
I do not believe there is a permanent solution, since this problem has been out for far too long with little interest to fix it. I would recommend having that terminal script save as a .command stored in your dock that you would click every time you need it. To create a document that can do this for you:


Open TextEdit.app
Enter the following code into the document:

rm ~/Library/Caches/CloudKit/CloudKitMetadata*;killall cloudd
Save to a directory with the name "[a name that you would like].command"
Open Terminal
Type in chmod a+x BUT DO NOT HIT ENTER
Drag in the .command
Hit enter


Now you can drag in the command to your dock and click it whenever you need

EDIT:

Another idea is to use Automator. 


Open up Automator
Go to the toolbar on the left and drag a execute she'll script 
Paste the code from above into the action
Record a "Watch me Do" (by pressing the red record button in the top right) of:


Opening activity monitor
Seraching for cloudd
Clicking cloudd
Clicking quit
Selecting quit or force quit


Set that to 1000x and save as an app