Is there a need to make it different? You're asking for change for change sake.Fully customized silicone, no more spinning disk or optical drive (for years), yet they couldn’t update the design 10 years later?
I'm sure those with accessories they'll be able to continue using with the new Mac mini will be happy. I don't see any need for change and have had numerous Mac minis throughout the years. If it ain't broke, don't fix it.