If you asked me the one thing you could change to improve your code, I’d tell you you’re asking the wrong question.
If you came to me and asked me how to improve the productivity, happiness, and knowledge of your software developers, I’d tell you that I don’t know. But I do know how you can find out.
Introduce pair programming, with frequent rotation. Pairing has a number of benefits that any XP fan (like me) will happily go into, such as getting very fast feedback on your work, keeping each other motivated, and learning how any part of the system works very quickly. I think an even more important benefit that doesn’t get talked about enough is that pair programming is a culture accelerator.
In a team (or company) larger than 5 people, 1 person can’t change much. However, a pair of people that agree on something can talk to others. With pair rotation, those 2 quickly become 4, then 8, and good ideas spread to the point where everyone agrees within days, without calling a meeting or needing a particular person to be some kind of champion for a cause.
Pairing, with rotation, means that a good idea in one person’s brain quickly spreads to everyone’s. When you’re pairing, you don’t complain about something, you improve it. That includes your company culture.
Don’t try and improve your developers' productivity. Make them do it themselves.