WWDC is about hardware issues half the time so it's not unlikely that mac mini could have come out with new form factor here.
If other hardware was announced & the mini was left out, I would believe it, but because there was no hardware announcement at all, I think there is still hope.
I have to agree unless a silent update happens. I'm just glad I got mine right after the last update came out
Mini isnt there just because its going to be a major revamp (Internally)
Any significant new Mac designs are almost certainly dependent on the new Intel Broadwell chips, and Intel has pushed those back to the end of this year.
There may be minor spec bumps before then, but they wouldn't warrant airtime at WWDC. (The Air has already had one, with virtually no fanfare).
Also, I'm sure Apple plan on waiting a bit longer to see how many more Mac Pros they can sell - now that they're becoming easily available - to people who don't really need Xeons or dual GPUs but still want a desktop.