On TW's defence, they have to make sure that everything is working smoothly before they announce that feature. Modders, on the other hand, is not doing all these tests. Not all of them at least. I'm trying to test all edge cases as far as I can before release anything however it's sometimes extremely hard to test some cases. Still personally I'm always trying to stay in line and preserve lore and game balance.
However, I must also say that everything TW adds is not also working 100% smoothly all the time, so it's almost impossible to cover every single case - and this is exactly why they have the Beta branch. Release new features, get feedback, fix it. Do that until it's no longer causing issues, and release to a stable branch. And 90% of CTD I receive is mainly related to unknown logic happening inside the TW's code or because I'm finding workarounds to that code - so if I had the source code, those wouldn't be in there as well.
As long as you are doing new stuff in the Beta branch, people will also stop complaining about slow updates as well - I seriously don't get why Beta branch and stable branch is getting hotfixes nearly at the same time.
However, I must also say that everything TW adds is not also working 100% smoothly all the time, so it's almost impossible to cover every single case - and this is exactly why they have the Beta branch. Release new features, get feedback, fix it. Do that until it's no longer causing issues, and release to a stable branch. And 90% of CTD I receive is mainly related to unknown logic happening inside the TW's code or because I'm finding workarounds to that code - so if I had the source code, those wouldn't be in there as well.
As long as you are doing new stuff in the Beta branch, people will also stop complaining about slow updates as well - I seriously don't get why Beta branch and stable branch is getting hotfixes nearly at the same time.