I understand the 2000 blocks as a rolling window like for other votes. Is that right? I’m asking because the passage that deals with the vote falling below 90%. This sounds a bit confusing.
If my understanding is right, I can’t find obvious drawbacks.
2000 blocks should equal roughly 33 hours or one and a third day.
The update time frame is only that short, if the majority of the minters is quickly updating and voting for the change. It might often take way more time than 33 hours from the release until the 90% are reached. I expect that users of NBT need to follow.
But even it goes that fast; it’s in my opinion enough time for both the remaining minters to follow the minting majority as well as the exchanges (and soon the merchants and other users ot NBT - hopefully!) to update their wallets.
Admittedly I’m not involved in running an exchange (nor a business), but I guess that more than a day (“worst case”; read: shortest time frame) should be enough - maybe I should say that I hope it…
Once the adoption is far beyond a bunch of users and some exchanges (ok, this one’s a little bit tongue-in-cheek) it might be appropriate to have another vote to expand the minimum time frame from making the new client version available until switching to the new protocol version.
This might become necessary because the number of NBT users (people, merchants, exchanges, etc.) will grow quicker than the number of NSR holders (possible minters) and the number of minting NSR.