First of all, you don't have to apologize and your english is quite good IMO.

You give some examples of what you wouldn't like to see, but I miss a statement what you d like spying to be like in HK. Should it be realistic (probably changing goals with your era progression) or do you like simpler, but effective systems like in moo2 where you can steal all the tech instead of researching them and even sabotage fleets. I like systems you have to invest in in order to be effective, but with a great impact in certain areas. What I wouldn't like to see is a spying system that is just there and therefore less impactful.

"Spying" as a system is usually quite badly done for a number of possible reasons.

1. At it's core, it is an extension of some existing and more important systems. Military spying to reveal troop movements and new weapons is so players win the military system. Economic spying to steal tech is so players win the economy system.

2. Actionable intelligence is difficult to produce in this specific type of game. Let's imagine player A is preparing to attack player B. An espionage system should be capable of providing popup warnings ("Player A desires this region"), specifically revealing tiles in the fog-of-war, giving a good estimate of enemy tech and forces. AI is usually not good at putting information together to provide players with direction.

3. Spying as a field has expanded in scope since the Industrial Revolution, so it would be hard to model this in a game.

-In-battle intel, with camoflage, ambushes, night battles, prisoner interrogation, recon troops and aircraft, psyops, electronic warfare, etc., could be an entire working system itself.

-Economic spying (for techs or destruction) in games are condensed into single tiles or single techs, which isn't realistic. With some notable historical exceptions, economic spying is more about slowly leaching technology to prevent the host nation from taking drastic counter-espionage action.

-Political espionage is highly important in the current world, especially against democratic cultures. This would cover disinformation campaigns and propaganda, internal spying on your own pops, all the way to assainations and installation of puppet governments.

-General information gathering would cover some situations like disaster preparation (for weather or disease events), or some military situations like monitoring ICBMs.

The difficulty is that any overt espionage action is, in some sense, a failure. Intelligence activities are entirely dependent on sources and methods, and the more you use your sources and methods, the greater chance that you will be detected, your agents will be imprisoned (or shot during war) and technical methods negated.

Maybe a fully fleshed espionage implementation should let you do dramatic things...once. But such activities as blowing up a factory or assassinating a politician would definately damage your ability to keep operating.

For an initial release, it would be better to have a sturdy "sub-system" of espionage "boosts" to support the major systems. It could even be as abstract as simply providing a budget in gold for spy features (i.e, if you have a spy district/building(?) at level 2, you can pay 50 gold to cause a riot in a random city belonging to any player). Later development could add bigger actions, and dedicated features.

Personally, I am excited to see how battlefield information warfare is handled, since I think there is a lot of room for improvement over other 4X titles.

Part of the problem is the point of spying is to gather information, but that information is often given to the player for free. For example in Endless Space you can see each players score in the upper left by hovering over the wings and if you go to the victory screen you can see your ranking. If that kind of information was not automatically given but must instead be obtained through spying it would have more of a point. Additionally granting vision of enemy territory, and knowledge of how many troops they have could be helpful. And although it might be impractical to implement an "open the city gates" feature on a game of this scale, you could get a bonus to siege damage or attrition speed for having a spy in the city before you begin your seige.