Questionable need, benefits and priority
At first sight this proposal has some merits but more thought leads me to question the idea.
Others have already commented on the need to avoiud duplication with other sites and perhaps cooperation in having a single site provide the required information.
Most patients have drugs prescribed and dispensed either simultaneously or within an hour or so. The belief this would be used by patients looking up a drug prior to taking it is not the case for the majority.
Many patients or carers do read the PIL and good GPs will ensure the patient understands what they are prescribing and why.
Patients who do research on the internet either before or more likely after getting the drugs will look for clarification of the outcomes from the drug and, perhaps more likely, potential side-effects.
Again, I agree with other respondants that the side-effect list is usually exhaustive, conservatively derived and thus not usually helpful. Some PILs do give percentage probabilities based on experience which can be more helpful.