People can go on all day about this. The most major one for me is protocol engineering - there's a whole world out there on this. Others would be model based de

People can go on all day about this. The most major one for me is protocol engineering - there's a whole world out there on this. Others would be model based design and its formal verification. Also several problems in state synchronization in distributed systems. In many of these cases, the team I joined had a code base in place that "kind of" did the solution, but was not grounded in any conceptual model - despite phenomenal code quality, peer reviews, etc. Recasting it as an implementation of a well-studied formal model generally yielded a codebase that was one-tenth the size of the original, and with far fewer defects. As I said in the parent comment, if you aren't familiar with this kind of stuff, you don't know about it, so you don't use it, so you find other (suboptimal) ways to do it.