Is the transaction history ok for this? Maybe a link or button on the first page after login would be faster than having to go through the menu at the top?
As another poster has mentioned, looking at transaction history only provides you with a good idea of the payout on the next block if there are no major changes in hash (personal or pool) before it's solved.
A user interface suggestion would be to bring that number back with a note that reads "What's this?" People would click on it which produces a pop-up with your explanation of what that number means including a note about shifts and maybe a link in the pop-up to more information about how your payout system works. You had a brief explanation before when you hovered over the title. Most people may not have known to hover over the title, whereas a "What's this?" link would stand out better. Plus, you have more room for an explanation in a traditional pop-up, then the hover over.
The default landing page after logging in could be called "Account Overview" or "Account at Glance." It would include bringing back the expected payout per block along with the other information that's there now. An overview of your current hash rate and your last few shifts that's on the expanded stats page would be useful on this page. I would recommend showing the last few blocks solved (with your payout for those blocks) and the time since last block solved with a note that you only get paid when a block is solved, not when shifts are completed.