Have you noticed that your "5 minutes to code" practically asks the same question as "Why does A17 take so long?" just with a different time frame?So an improvement that takes 5 minutes to code should be left for last because it belongs in the polishing stage?
When I got my first computer a long time ago I wanted to show some relatives what you can do with computers. So I programmed a 10 line programm to print out 6 random numbers between 1 and 49 for a lottery. With my relatives waiting behind me I had the program written in 2 minutes but then spent more than 5 agonizing minutes removing a surprisingly large number of bugs I crammed into those 10 (!!!) lines of code.