Friday sessions are a hangover from the 2 day qualifying format but even so, Silverstone still manages to sell out because its a chance to see the cars on track for 3 hours.
Sprint races, hmmm that would only work if cars could dice wheel to wheel for 10 to 15 laps. Under the current regulations, that's not going to happen.
When you think about it, F1 seemed to be at its most popular in the US during the 80's when the cars were huge, fire breathing, 1000hp beasts that either finished or exploded.
Any attempt to appeal to one set of fans will only end up upsetting the majority.
This has got disaster written all over it.