It's not a terrible idea in general, I personally think it's potentially a great idea, but like you I do think the Raspberry Pi was a poor choice for this use-case.
Perhaps in the next revision they'll base it around something better suited, such as the ESPRESSOBin:
The Raspberry Pi is the obvious choice because it’s very widely available. :) Raspberry Pi 3 compatibility is coming with the next version.
For Nextcloud itself people like to of course hate about it being in PHP just for the sake of it. But the simple fact is that it enables a lot of people to run it. And if we want a viable alternative, then that is paramount.
This looks like a great piece of HW with a Drobo mini attached. It could be a great daemon/cron/storage box with only one ethernet port, but w/ three it seems they are positioning to compete with the ERL3 from Ubiquiti which has a MIPS-based cpu from Brocade.
Perhaps in the next revision they'll base it around something better suited, such as the ESPRESSOBin:
http://www.cnx-software.com/2016/09/23/marvell-espressobin-b...