- After upgrading to CQ5.3 I can no longer access the site by excluding "/content" from the URL.
- When I try to add the /content/-/ mapping back via the /system/console/configMgr ResourceResolver configuration then after we restart the server the change is lost.
The /content/-/ mapping was removed in CQ5.3 and the loading order of Apache Felix configurations have changed in the version of Felix that ships with CQ5.3.
For more information on the Felix configuration loading order in CQ5.3 see this article 
You can re-enable the /content/-/ mapping by doing the following
- Log into /crx as admin
- Open Content Explorer
- Create the folder path /apps/sling/config using sling:Folder node types
- Copy this node
/content/-/to the String property
- Click Save All