I honestly think the most important 'bug' that needs to be examined is the 'memory leak' or whatever it is causing
gradual performance degradation over repeated play. There have been several posts about it in various parts of the forum - and no word from Luthier...
The sim still isn't performing anywhere near the level it should be, I'm a bit horrified that they're almost out of improvements! Until the performance degradation is fixed, any improvements are hard to test properly - and of course it's not doing wonders for the gameplay.