As we know, there are 'hidden' attributes for every player - these are vaguely revealed through scout reports and player personality descriptions. I propose that a manager should be able to 'uncover' a players hidden ratings over a long period of scouting and research - in order to make more informed decisions when buying players.
So you would be able to assign a scout to watch certain players over say half a season or a season, and the more games they play the more the information the scout compiles. He can then provide a more detailed (though still not at the level of actually listing each attribute) insight into his mental attributes.
Each scout would be limited to a certain amount of players he could track (limited by say, his Determination) and his ability to uncover hidden attributes could be determined by his Mental (knowledge of mental player ability) attribute and his Man Management (ability to get to know the player, get to know his entourage, do serious research on him from people who work with him etc). Scouts of lesser ability would produce more vague, less accurate reports or simply take longer to produce the report.
This would improve scouting overall as scouts would have more attributes which are important for them, meaning you could have 'net scouts' (scouts who watch a large group of players and give brief report with recommendations) and 'sniper scouts' (scouts who specialise in finding out hidden attributes) so you could build up a team of different specialists.
Another suggestion is to have scouts with different 'scouting styles' which influences the types of reports they produce for you. So you could have scouts who do a lot of statistical analysis, they would provide you reports which interpret all his playing statistics in detail and compare them to players in your current setup; scouts who watch a lot of games, they would give you more accurate analysis of his actual ability; scouts who get to know the players and give more detailed reports on their hidden attributes.
So again, you can build up a different network of scouts who serve different purposes - I think it would expand and improve this imo underdeveloped part of the game.
It would make sense to me if you could ask a scout to find out a particular type of knowledge like consistency/big matches/transfer fee/wages. They might not succeed but they should stand more chance than a general scout report.