I first collided with KSP at v1.0 (2015), and remember how hard it was to reach orbit with my noob rockets. This was just like high school physics, where I repeatedly failed to even understand the concept of orbits. But this game captured me, and Principia (with its more advanced n-body mechanics) is now my all-time favorite mod. As a "serious game" or edutainment sim, KSP is absolutely unbeatable.
My first mod was a tech tree - OpenTree. It was definitely an amateur effort, but there was a lot of community input, particularly from one forum member who taught me about the design process. There were two key technical problems I aimed to resolve: the seemingly arbitrary groupings of parts in technologies, which often resulted in illogical development; and the science gathering - where e.g. temp scans and crew reports unlock bigger engines - which I found immersion-breaking within the semi-realistic setting. The former could be quickly solved with Module Manager patches, but it would take almost a decade of design iterations, self education in c# for Unity, and two solo overhaul mods to solve the latter. In the end I'm overjoyed that I got there, and gained more than I could ever imagine in the process.
I'm a designer first, programmer second, so this design solution is my most valued contribution. For various reasons, few people will see or appreciate it, so I'll try to summarize here: it involved first adding incremental damage tracking to parts, recorded by type (e.g. repeated smaller impacts could eventually destroy parts); then converting that damage into science of that subtype upon recovery. Part technologies were also grouped by type, and required that subtype of science as an additional prerequisite. This provides a more sandbox-style R&D system, where players can do pretty much anything and be rewarded with science and progression, while still having to focus on specific tasks for specific goals (e.g. engine tests to develop engines).
I've poured thousands of hours into modding by now, and after also seeing a smaller one end up in a base game, it's time to move on. One of the first games I really loved was Space Station Silicon Valley for N64, but my last game before the KSP franchise was SimCity. Fighting that niche-devouring corpo trend requires a lot more than just programming skills. At the end of the day, I'm more of an activist at heart, so I'll always be inclined to tell lawyers to go "F" themselves and walk away with nothing.
Bye