As I thought yesterday, the change with the highest implications and which will need a longer time to find its optimal parameters is the new resource credits system.
A confirmation for me came later, when I read 
So after the hard fork, if everything goes well, a few things should be clear:
- curation window reduced from 30 to 15 minutes; see yesterday's post for more!
- authors' self-curation advantage removed
- delegations returned after 5 days instead of 7
- possibility to comment every 3 seconds instead of 20
- unlimited editing of posts even after 7 days (already possible)
- SBD rewards will be received until debt ratio reaches 9%, instead of 5% now
- both upvotes and downvotes can be given in the last 12 hours of the payout period, at increasing cost with passing time
- dust votes will be worth nothing below a certain threshold (should disincentivize spam votes)
- account creation fee will be burned instead of powered up; connected to this, there will be no minimum SP power down restriction
- possibility to create accounts with delegation removed
- beneficiary rewards will follow author's rewards setting
- internal market orders expire after 28 days (from never expire now)
You can read details about every one of them here.
What will be still be in a kinda fluent state for a while is everything connected to the resource credits system. That influences every operation an account can do on the blockchain, including the newly introduced possibility to create new accounts using RCs instead of paying for them with STEEM.
While the next week or so may not be the greatest from the user's experience, especially if you have low SP or you have a highly active account (one that runs a bot for example), this is a necessary step to calibrate the real consumption of resources on the blockchain in the perspective of scaling up.
Tic tac, tic tac! Less than 2 hours now... :)