Suggestion: Detailed premium time remaining tooltip
The "always on" display for premium time rounds time remaining up in 1 day increments. The only way to know how much time you have left *exactly* is to build something and look at the detailed time remaining on the last construction slot.
That's an inconvenience that should be simple to fix. Take the time remaining displayed on the last construction slot and display it, in real time, in the tooltip you see when you mouse over the 'Premium Time' section of your portrait.
That would be a great quality of life improvement that should be relatively uncomplicated to implement with high impact and high visibility to your player base.