Even on Linux x86 Desktop PC, KODI install doesn't just work out of the box. Sometimes you need to do manual hacking to fix things ... here is harder, since community is smaller and scattered around different hardware and development never reached proper level. Even with large community around Rpi it took years, before Openelec become stable / usable.|
Yes, Kodi on top of Debian is possible in theory, but it requires a lot of work, while porting Openelec, a dedicated KODI system, is way more simple.
Most other general purpose boards are better than RPi in almost all scenarios, they have better board design and on board hardware (eMMC, dedicated USB ports, separate gigabit network ...) , stability issues are fixed, especially on older boards, most boards are getting mainline support.
Main advantage of RPi was it's videocore, but both H3's and Odroid C2 can compete with this now and on top of this they have HDMI 1.4 / 2.0 which means 4k resolution 30/60Hz + much better board design and HW parts.
You can run Openelec with almost the cheapest OrangePi (shipped One 13USD, recommended rather PC 24USD).