I just purchased a Roku TV and after spending sometime with it i found a few limitations that are a bit bothersome. I'm not sure if the forum is the correct place for feature requests, but i searched and saw there had been such posts in the past. anyway...
1. SSA/ASS Subtitle support. I watch a lot of anime, so this is really limiting. I imagine it would be better for roku's ad revenue for me to stream directly on the TV instead of my xbox?
2. Disable Motion Smoothing. it's not a problem for inputs since i can enable game mode, but for streaming it makes all the movies look like soap opera's. It was really disappointing when i bought a $20 4K movie and it look so bad.
3. HDMI Black Level. The blacks are too dark on my ps4/xbox. This looks good for movies, but for video games it's too dark. I've tried adjusting brightness/contrast, but even with it all the way up some dark objects are too dark. Honestly I've been playing around with it for a while, and i'm pretty sure the tv auto switches depending on what the output is but no mater what i can't get it to look quite right.
2 and 3 could be implemented in the Expert Picture Settings of the app. It's a bit weird that these aren't already options, but extensive white balance and colour space setting are...