Just played and enjoyed my first 2 games of DA. While playing and using spies I found it a bit unrealistic that you are able to spy on all (visible) enemy planets and get to know about the planetary improvements in just one turn, requiring only one spy even on the lowest espionage level.

My idea of changing it could be combined with the active/passive spy idea posted earlier.
After you have selected a certain planet and decided not to install your agent, you have to keep him there at least one turn (after all it takes time for the agent to gather intel and reach his extraction point ) ,possibly in a passive non-detectable state.

I think it would make spying more interesting / difficult on lower espionage levels, keeping a player from 'scouting' all available targets in one turn and then selecting the best option...

What do you think?