I'd be pleasantly surprised to see it at WWDC but who knows... However, it's likely gonna be sooner rather than later, so it would p!ss me off too much if there was a significant change (aside from M2) from the M1 model that I just bought 3-4 months earlier.The rumors about WWDC are strong enough now that I'm tempted to just wait it out and if nothing comes out at WWDC then I'll just order. I know the M2 probably won't be that much more powerful but I'm hoping that maybe it's more than just a spec bump. Maybe they will add back in the SD card or add some more usb-c or usb-a ports to it. What I have right now Mac mini 2011 is kinda slow at times but it gets the job done for now. I can keep using it for another 2 months if needed.
I think there is a decent chance the new Mac mini will be out by fall. At that point, the M1 Mac mini would be two years old.