YES, you right we should be more upfront about RAID doesn't save you from doing backup. We will also highlight the fact that with OpenMediaVault you are able to program easily the usual scheduled backup routine (usb, ftp, rsync or upload to cloud drives).
A serial port and GPIO? This isn't a Raspberry Pi. Drop those.
Really ought to have dual NICs. (The SoC supports 3.)
Also should have x2 PCI-E slot for additional SATA ports. (The SoC supports those too. They won't be fast, but that's not what matters.)
Barrel connectors for DC input are a lot more common, IMO. Certainly more common with the "maker" and DIY community.
Maybe you've addressed this, but the "reset button" bugs me - that should be part of the front panel header too, if it isn't already.
Make sure it supports boot-from-USB. (Documentation on kickstarter page unclear.)
Other than that, I just hope you make the web interface really, really easy to use.
For a v2.0 project, maybe try to implement out-of-the-box integration with cloud backup services (OneDrive, BackBlaze, Crashplan, etc.)
Helios4 is meant to be both : a turn-key NAS solution, and also an open board for the people who have something else in mind.
We had to make some trade off because mainly of space constrain, and also the SoC has only 6 SERDES lines that can act either as PCIe, SATA, USB3.0...so you can't have the full combo. We chose an additional USB3.0 over an additional Gigabit because not so many people have the use for channel bonding....but I agree that everything is arguable.
Regarding the use of 4-PIN Kycon DC-IN connector, it's simply because 1) You won't find easily a DC-IN Jack connector with 8A rating 2) Most NAS with 12V DC input use this type of connector because of the PIN current rating. It make it also easy for people to find spare.
The reset button, is a CPU reset, not really meant to be pressed by mistake when you run NAS. The panel header has a soft button that triggers a graceful shutdown||reset sequence.
You can boot from USB from u-boot. There is an onboard SPI NOR Flash to store the u-boot, from there you can boot automatically SATA, USB or Network without the need of any sdcard inserted.
We have partner with OpenMediaVault which provide a Web UI similar to Synology DSM with many plugins. Some of those plugins allow to setup backup/sync to some could service.