I agree but doubt they will go for it. Despite the frustration caused by this issue being a cause of me getting somewhat disallusioned with the game. I spent money for more building licenses and having used them for more farms the extra field building actually makes the game more difficult. Having to come back to the game every three minutes is an utter pain, and making it six minutes with an increased queue isn't much better.
If leaving them out of the build queue entirely is too much how about adding 'repair fields' and 'repair wells' tasks. When added to the queue (and reach the top) they start repairing an exhausted field/well when finished they go onto the next and continue to do so until there are no more appropriate exhausted resource when they are cancelled and removed from the queue. You could put them on before going to work or sleep.
You have a problem that at the moment if you don't want to sit there for three minutes while three fields or wells are built (and lets face it, who does) you need something else to do. Another game fits the bill nicely. And then you find that actually the other game is much less of a pain to play and begin to wonder whether it's worth sticking with Settlers.