I wonder if Apple's engineers are even addressing it. These problems (dropped emails, blank email panes, etc.) first appeared in Lion and they continue to persist. What's the solution? Drop Mail if you have an Exchange server to deal with?
In 2008 Steve(Apple) bought Microsoft sync from Microsoft and have been using Microsofts Sync since then. So if the Microsoft's Exchange Server is 2008r2 or better Apple OS X+IOS with synced with them with no problem. Microsoft wanted to force businesses to upgrade the Exchange Servers if the business wanted to have Apple devices connecting to it.
So anything earlier than 2008 in Apple or Microsoft will need a "hack" or third party program to properly sync to work.