Sticking a Fusion would have been the right step up.
I was buying the previous ones as a default choice for anything from lab machine, through devel machine, house server and even small desktop.
The 1.3 (earliest) to 2.2 (latest) dual core low power Athlons provided more than enough power while running totally fanless (It was operating at 800 when idle not all the time - article is wrong on that). Decent onboard storage controller and disk cage, decent onboard networking, enough space for 2 more PCI network cards or PCI network and a low power video. The only let-down of the old model was the rather ancient video. A basic E450 or similar low power Fusion part would have solved that. A via Nano 64 bit model would have been interesting too. While its performance leaves a lot to be desired, it still kills everyone else on encryption - line rate crypto for all data on the machine. Rather useful feature for a server you can drop in a bag and walk out with. There would have been a niche for that too (nicely matching current HP thin client lineup which is Nano based).
Moving to a Celeron and corresponding Intel onboard chippery is a total step down compared to the older design on all counts. The video which was a major let down got worse (do we like it or not but the crowd likely to use a microserver is also likely to use a GUI). The performance in 64 bit mode too. Running it with inline crypto for the filesystems on a celery ? You gotta be kidding.
It is not a proper upgrade - it is a pretty badly executed downgrade with marketing fluff on it.