I just happened to me again, by the way. I exited a game that I stayed to finish and it asked me if I wanted to join my game in progress. This time I clicked yes, and it has just been stuck "Searching for opponents" ever since.
Mostly all of the points you mentioned have been discussed here in the forums in one way or another:
We are currently implementing automated punishments for leaver and staller (these implementations are rather complex and we need to test them in great detail to know they work properly).
The punishments include:
ELO deduction when leaving the game (it will be as if the player lost the game)
Remaining players will gain ELO as if they had finished with all remaining players
We rework the Timer so it won´t be possible to stall a game
If reported intentional quitters will be banned from the game depending on the number of violations (the same as it is now)
You should not only read rules but read forums and read in general, otherwise it seems that you can only write - in that case it will take some time for evolution of you to take over and give you ability to read as well.
Also, are you using windows 10? Windows 7? Do you think there is any issue with Windows 10 which I am using? I will make a guess that many more Catan players use Windows 7 than Windows 10. I wonder if Catan even works with Windows 10. Just had another Great/Greater Catan game crash on me without being able to re-boot and get back in. Ouch!