A new Mac mini would be the most boring thing they could put out right now. That's a really niche market.
For many, a Mac mini was their gateway drug to the Apple ecosystem, since it is the lowest priced Mac. In that vein I still see there being a reason for it. I only hope that if they do update it, they drop the "mini" and let it just be called a Mac (akin to iPad versus iPad Pro, iMac versus iMac Pro, MacBook versus MacBook Pro, Mac Mini versus Mac Pro? Nah).