I expect there is probably a lot of hoarding right now as people get use to the value of the credits.
I also think that AC may actually end up with less buy ups for some. In the past people would face a year with a number of NAV and SWUs that could only be used if you bought up. Now you have the potential to use all of your credits for the equivalent of SSWUs. Perhaps fewer upgrades overall, but unless you do a rational analysis of your total plans you won't figure out until too late.
The stronger application of the rules and no chance of an agent not lifting the cert will also affect the upgrade activity.
Let's hope op ups become more frequent as I'm hoarding my credits for now too.