Am urrently playing as Tarth (trying to become a great naval empire!) and I had some beginners problems with building a fleet...finding a beach, getting the right research. That kind of stuff.
Then I realised that one way to help or change this system would be a more situational research system. You meet a river. Now you can research a bridge. You find a beach: fishing! And so on a so forth. For most of the stuff this makes pretty good sense since your empire is not really inventing things but rather re-discovering them. Some things should obviously be availabe to research since people would remember them. But the more difficult things should only be available when you "need" them. A kingdom based in a desert would never begin researching Fishing. Of course if the player is there he would just not do it, but realistically they should be totally unable to do it before they encounter an ocean.
The only games I can remember that had this were some of the early Sierra first person/strategy games from the early 90's. Rebellion was one I think and Alien Legacy. There were probably some more.
Anyways I think this is a really cool idea but to be honest I don't know how well a game would play with this system installed. If you "miss" one of the triggers it could probably cripple your empire, but role-playing wise it seems awesome. And it would avoid the situation where a large kingdom can sit somewhere and slowly build up and then whammo! expand into an area they have never been before using some knowledge they shouldn't have been able to know. Sort of like the cultural and military Tradition in Europa Universalis 3 works. Only an empire who has consistenly been at war for long will have good generals etc. But not necessarily good army tech.