As a person with a 2014 LG WebOS 55" smartTV, let me tell you this. The likelihood of it getting an update past the year it's released is next to zero.

I like the UI, enjoy the speed, don't like the Magic Remote too well (wife hates it, that means I should too... but I like the absence of buttons).

If you're looking for cards, and other WebOS standards from the Palm/TouchPad, you'll be disappointed. On the backend, it seems like they stuck pretty close to Open WebOS on the backend. But if you're out to tinker with it, I doubt they'd allow it due to the inclusion of the store, et al (willing to bet they used certs, et al that aren't readily available to the open source)

Personally, I'm leaning more and more to a "dumb" TV and perhaps one of the Intel HDMI (like this) and making my TV into a display for whatever is attached to it and will allow me to upgrade and tinker as I see fit.

Just a thought. But so far, what I've seen supports the open WebOS statements above. I've yet to really dig too deeply though. Perhaps will once I get some time...