Thanks for the arch system for Raspberry pi. Here are some points for discussion (currently I am trying it with qemu and waiting for the Rasperry Pi shortly)
As the archlinux-ARM is also switched systemd, syslog-ng service can be disabled in the image file imo (this will also saves some writes to sd card).
fstab: requires both / and /boot to be mounted with rw option and can be updated in the image file.