I think there were three problems with scouts in the first game: a separate supply from ships, too cheap of a cost, and visibility into the system even if the scout was destroyed. As a result players built a lot of scouts and had fairly consistent intel across the map most of the game. Cardona had 8 scouts, Eldrazi 7, and Quetzelquidian 6 across the map on the final turn and combined with their ships and colonies a large percentage of the map was exposed for little cost.
There are a few minor adjustments that can help with this:
-More expensive scouts – push the decision to make a scout or not a little bit more. They’ll still remain cheaper than ships, but not quite as cheap as $5 – maybe $10?
-Share supply with ships – Ship supply will be increased compared to the previous games but you’ll have to share the supply with your other ships.
-Destroyed ships no longer grant info – if your ship gets destroyed, you don’t “see” into that colony.
Or, I could depart from the cheap scouts overall and implement a more complex system for spying with Stealth Ships as a possible ship class:
-Cost the same as regular ships and shares supply
-Available as a class purchase at level 1 engineering
-Each turn, the ship rolls a 1d6
1: Ship is seen and immediately destroyed (based on diplomacy)
2: Ship and owner are detected, but ship is not destroyed
3: Ship is detected, but with an unknown owner
4-6: Ship is not seen
You definitely have a good chance to spy on your enemies and allies with this but do have a chance of getting detected or destroyed. Obviously the odds could be tweaked as needed to grant a sweet spot between the two. Because the ship can’t attack having a whole fleet of these would put you at risk, but it could potentially setup a supportive role for empires in a war they otherwise may not be involved in.