When it rains, it floods. So easily, so thoroughly. If it were real life, the race would be red flagged every time. The 3rd chicane also to a lesser degree. I know LiveTrack 3.0 is doing its thing here, but it need to be faked a bit in those two corners - simply for the sake of gameplay. A fake drain should be installed 'cuz if it rains even a bit, that's it, you can't drive through it. The AI can, tho. But I don't think the AI should be tweaked here - it should be the track. Let's get one or two or several drains in there and keep that part of the track from becoming a lake.
I have no idea if the track flooded as badly IRL as it is in the sim but as it is classic version of the track i doubt they would have red flagged it anyway in that era. Christ! They would not stop races when a fatal crash happened a lot of the time... The AI still are affected differently by the climatic conditions as they run on a simplified model to the player. Gameplay vs accuracy of simulation, thank god i'm not a racing sim/game developer. I always associate classic Hockenheim with the tragic death of Jim Clark and what could have been for such a talent...
If you find Hockenheim bad, just try classic Imola, almost imposible when soaked with all the lakes that form all over the track, specially after Tamburello.
