Bring back a feature from CIV...

[VanitysFiend]

...and no, I'm not asking for stacks, but if u could that would be nice

Anyway, CIV had a feature where if the show tile yields button was ticked unworked tiles showed up as translucent and recessed/small, and worked tiles showed up as opaque and a bit larger. This allowed players to see at a glance which tiles where being worked without having to go into the city screen, which admittedly was just a double click away, unlike some games I can think of...

 

[Roxlimn]

You can see which tiles are being worked right on the overland map.

 

[stormtrooper412]

I'm really looking forward to the EUI mod which is hopefully already in the works