My review differs a bit in that my Mac Mini is nearly spec'd out, w/ the i7, 64GB ram, 10Gb eth, and 1TB SSD, which I purchased as "refurbished" for only ~$2500 (compared to the original price of ~$3500+ if I remember correctly when it debuted).
I'm a software engineer. I wanted the extra cores and memory to run multiple virtual machines and/or containers without having to worry about resources. I also own a spec'd out 2018 MacBook Pro 13", but felt constrained at times with my development needs, trying to squeeze everything into memory at once.
The fact the new MacMini uses a desktop class CPU (prior generations used mobile processors) which in turn allowed it to support 64GB of ram (you can thank Intel for that restriction on their current gen of mobile processors) made this model a massive upgrade over not only my MacBook Pro but also prior generations of Mini's. I won't go into details, but I will say it's both noticeably faster than my MacBook Pro, and it's faster while simultaneously doing more things at the same time.
As for GPU, I'm not a gamer or working in AI/machine learning/etc, so it's not a bother at all. However, if I were any of those things, I can almost guarantee that I'd be unsatisfied with anything Apple offered in the Mini anyways. The combination of Apple rarely using the latest/best GPU options in any of their products combined with the Mini's limited thermal capacity (which is already being consumed by the upgraded desktop-class CPU) means I'd undoubtably want to upgrade anyways. External GPU's are becoming far more common, and this is a perfectly fine tradeoff that also allows you to upgrade over time. Anything else would require a dramatic resizing of the Mini and also likely dramatic increase its price. Instead, they give us 4 Thunderbolt 3 ports to take advantage of if we so desire. Perfect for my needs, and even though many people may not feel it's enough, it's probably the only feasible solution without major tradeoffs. I'd be disappointed if they downgraded the CPU to a mobile (e.g. cooler but slower) variant and then included a mediocre GPU. It'd be a lose-lose situation. You'd have a slower machine overall, and still probably wanting faster GPU performance which would still require an external GPU.
In the end, I'm not a fan of my computer being embedded into my monitor (unless it's my laptop) so I much preferred the Mini over the iMac. I couldn't be happier with my purchase. When it debuted, it was the fastest computer in Apple's lineup (on GeekBench) except for the spec'd out Mac Pro. That's pretty impressive given its form factor, and when you consider that, the price wasn't unreasonable at all.
If I had any complaint, it would be that the SSD is integrated and cannot be replaced/upgraded, so don't be frugal when ordering. In general (up to a point) SSD performance and lifespan is improved with increased size. So go big or go home, because you won't have another opportunity.
I've owned a variety of Mac Mini's over the years. Some at home, some colocated at server farms, etc. In my opinion, this is perhaps the best Mac Mini that's ever been made. It's a close call w/ the late 2012 + 2013 + early 2014 Mini. That model supported quad-core, and had not only upgradeable RAM but also dual upgradable HDD/SSD drive bays, which made it incredibly flexible in terms of configurations.