I think history is a better guide because we can more clearly see what was valuable. Things that were censored in the past:
* Heliocentricism
* Evolution, esp of humans from other apes
* Capitalism/market economics (in socialist states)
* Currently mainstream views about biology (e.g. Lysenkoism)
Free speech is a "hits" business: most of the value comes from a few incredibly valuable ideas that someone powerful is trying to censor. The damage done to Russia and China under communism easily exceeds all the extra "smoothness" that they got out of censoring those who disagreed with them.