AFAIK there isn't anything interesting coming in Kodi 18. I've been using Kodi/XBMC/XBMP since the early XBOX days, back then there was no media players or PC's you could hook up to the TV. Today we have smart TV's that can hardware decode the media themselves. Unless Kodi can do a better job, then there's really no need for it. Plex uses an elegant solution, letting the TV do the work and presenting the UI through a web app. I can control the UI with the LG magic mouse, subs are downloaded automatically by PMS and most importantly there is HDR 
Just the fact that Kodi still requires you to manually update and clean the library shows how obsolete it is (yes I know there'as addons for this functionality but in the past they sucked). Now they added support for running libretro cores inside of Kodi, which IMO seems like a terrible idea as RetroArch will always be superior and better maintained.
Basically, I need(ed) Kodi to present my media and play it in the best way possible. Now there's better options, at least for the time being. We will see what happens, but HDR for Intel or AMD is still far off I think. Up until now I had a 3D capable TV but Kodi still does not support MVC so I never got to enjoy that (except for inferior SBS or OU). Plex could direct play the content but the interface sucked on my older TV. Times change and I'm done missing out.
End of rant, we'll see what happens but the future doesn't look very bright. Unless you got an LG OLED of course
