Back in the golden days, the bot frameworks rsbot/powerbot/rsbuddy gave you a Java API into the game. Your script gets called every game loop (by the API) and you can tell your character to walk to places, click on things, pathfind your way around the game world. The API could access your player's levels and experience and gave your script (a Java class) an onPaint event to draw a GUI.
Botters were spending their time learning Java, on the forums were people talking about more in depth programming concepts and ways to improve code quality. The bot frameworks were open source (with the exception of "modscripts" - a series of regexes and what not to remap the bot APIs back into functions in the obfuscated Jagex client).
Jagex has also implemented turing tests - "random events" where your character get teleported a special area and has to perform a challenge. The bot framework has scripts to handle this as well and was generally not a huge issue.
The best part was that it was all real, if your code misbehaves, people will report you and you will get banned. If your code works flawlessly, it will run for days and you'll get rave reviews from fellow botters on the forums.
If anything it was a great environment to develop CS skills. And of course after you botted up your stats and unlocked new abilities the game becomes even more fun.