Do you ever contribute to a conversation about something like this without finding a way to abuse Silverstone?
No, I'm genuinely curious. It was a problem because there were large puddles of standing water on the surface of the circuit. It's always been an issue because the circuit is in a large catchment area, so it takes a long time for the water level to drop. But on this occasion, there was unseasonably heavy rain. I remember
Autosport running a story about the congestion and chaos because people were missing practice and qualifying. There were promises to fix it, but I don't know if anything was done - the British Grand Prix is the only major event that I see at Silverstone (I don't have the patience for the WEC and we don't get coverage of anything else), there hasn't been a seriously wet race since, and there was no follow-up reporting done. I assume the drainage was improved, but I haven't seen any confirmation of it.
Also, if I were to go to a Grand Prix for three days, it would cost me at least a week's pay (blowing my budget for a month) and I would need to take two days off work. If I then couldn't get into the circuit for Friday practice because poor drainage limited access, you'd better believe that I would be pretty damn upset about it. Especially if proper drainage wasn't figured into the design of a major reconfiguration.
Now that I think on it, I suspect the work was done. When Kimi Räikkönen had his massive accident a few years ago, it was because he hit a drainage culvert when rejoining the circuit at Aintree. He was criticised at the time because he hadn't done a walk-around to inspect the circuit; if he had, he would have known about it becauelse the culvert was new. That suggests the work was done.