I think they still want to differentiate their line-up and Mac Mini had to suffer. If Mini was on par with rMBP it wouldn't be Apple style. They don't only put tiers for each product but each of their products is tier of its own.
UHD 630 is very weak GPU. In old line-up it would MBA tier. It's funny because this time MBA gets even worse GPU. It only sounded semi-decent in Keynote because they compared it to Mac Mini base model from 2014 which came with HD 5000. If they compared it to rMBP, it is 25% slower than current 13.3".
I really wanted to get this Mini but it would honestly be downgrade for me. My Intel NUC Skull Canyon is smaller, has 60% faster GPU, 4 core 8 threads Core i7, 16GB DDR4 RAM at 800$ (that's with Windows 10 and post 23% tax). And the best part, it was released two years ago. I can get Intel NUC Hades Canyon which has same volume as Mac Mini but packs VR ready AMD Vega M GH which is 478% faster than new Mini for only 1250$ (also with W10 and post 23% tax).
Why am I so obsessed with GPUs? I like from time to time to play SC2 which is 8 years old game that will struggle to run at FHD and medium preset on Mini from 2018. It might be silly, but I'd have to get 1100$ mini wiht 700$ eGPU (and 50$ active TB3 cable that isn't 50cm long) and then add 23% tax to it not to downgrade my current setup.
macOS isn't worth this much for me.
EDIT: If anybody looks up coputers I mentioned, both come with interchangeable covers without edgy skulls (aka. just blank black plastic).