Overlay is a very important and helpfull tool to check your island's condition.
With one option active you can hover cursor over some area\building to see it's value within chosen overlay type. However, the info of an object is shown at the overlay window and is constantly updating, so this window is wobling all the time and is really disturbing (At least that's the problem in russian version).

I suggest 2 ways for an improvement:
1.)A tooltip at the cursor showing the value while in overlay mode;
or
2.)The second way that would make me very grateful is if colored info would change into a text info, so instead of seeing red-to-green buildings with overlay active we see numeric values (current\max) above each building (probably while zoomed in a little).
Both of my suggests are way more informative and easier to read than current in-game tool. (IMO)

(and yeah, the game already features tooltip near the cursor, so i think it is not very hard to implement)
However, i love the game. You guys made a real progress with almanac, for example. For the first time in the series this thing is a real saver and you dont feel pain while using it ;)