User Profile Sercvice Application
A little less complicated and UPS configuration will definitely help and reduce issues that occur during and after configuration.
I would like to see a better integration with AD (example: if I delete an user in AD, he\she continues to exist in SharePoint)
John Wills commented
Information on how to clean up failed UPA instances is always helpful.
Umar is you concern on the sync setup or just deployment of the service application itself.