I agree that having long governance periods is slow and can be inefficient. However, we do need to have them. We cannot have a completely liquid governance because voters should be required to have a commitment to live with the consequences of their votes.
Further, if you had too many voting periods, many would not want to participate due to it being too much work. While some might say that is a good thing because only invested and informed governors would remain, I think we should rather try to make it as accessible to as many as possible. This is the only way of making it “very” decentralized. With this in mind, I think we should try to keeping it simple and inclusive.
Not having governance periods is not an issue in Cosmos because they use bonded PoS.
Having too many voting periods I think is already being seen as an issue in Cosmos. Some chains have really frequent votings, and also on very specific issues on the protocol level. That is why a lot of people simply automatically vote yes. Rarely I see people admit they are not informed enough or interested enough to abstain from the vote.
Therefore, I currently think quarterly governance is a good compromise for both of these aspects, and the updated suggestion as its implementation possibility.
I would not set this as a requirement because it could turn out as a single point of failure. But it could be a recommendation. And in practice, if a proposal would not be discussed first, it would most likely not gather enough support to even come up to a vote.