The simplest solution I can see to the "problem" of getting too much crop in return for stolen goods would be to pay crop in the same proportion as other resources. Don't link the amount of crop paid with the number of treasures in a kingdom. In the FIS, which has gone far beyond where a 1x server will go, I find myself selling stolen goods from my cap and overflowing the granary by 100s of thousands in crop just to fill the warehouse. While it will never get that extreme on a normal server, the same thing will happen.
Just throwing numbers out - for Gaul, 600 wood, 800 clay, 600 Iron and 800 crop per stolen good would seem reasonable at this point. Another way to do it would be for each stolen good to pay a percentage of the server average amount of each resource, including crop, taken in bounty from hideouts.
As we have discussed before, there is indeed much too much crop in this version, and a good part of the reason is that crop cost for troops and crop fields has been taken out of the game. I still feel crop should be included in the cost of research, training and upgrading of troops and in all buildings and fields. Even if this is done, the ridiculously high payment in crop for stolen goods, later in the server and especially in the larger kingdoms with a large number of treasures, is a deal breaker for a high percentage of players. I am a heavy gold user, yet I will tell you now that this aspect of the new game gives too much advantage to gold users. Set the values so crop is not linked to a kingdom's treasures.
We still tend to think in terms of earlier versions, however. We need to stop doing that. TK is a different game in so many ways. We have to find new tactics, new strategies. We have to work within different limitations. But with a few basic changes it can be a better game than T4 ever was, can encourage teamwork, and can be much more fun.