Builders need to grow in experience based on what buildings they build and the "difficulty" it takes to build that building. Introducing a level up system for the builders will allow them to gradually grow more efficient (as would happen in any real scenario) and have an effect on the time it takes to progress. As a system CoC could reduce (by a moderate amount) the amount of time it takes to build buildings as builders grow in level (say to a max of 25%) and maybe even the cost/resource requirement (say to a max of 10-20%). Each builder would of course progress based on what that individual builder does (so hopefully CoC has some background log to show which builders did what). This system would make the game more dynamic allowing people to choose which builders they want to use for which buildings and allowing people who are not willing and never will be willing to buy jewels (such as myself) the opportunity to be rewarded for the increased play time they need to progress. Could do the same thing for barracks, making some troop creations worth more experience than others leading to a quicker production time and a lesser resource cost as barracks upgrade. These changes would have a minimal effect on the actual game and the amount of time/resources is needed in order to progress, but it would be enough to lead to a system of accomplishment and satisfaction in the fact that we are at least getting some sort of time/resource discount as a reward for our effort.
