Yes, a proper Plex app will be nice.
In the meantime, you can use the browser to browse to your Plex server and get the Plex web app. It's a little slow to browse but otherwise works fine.
Or, what I have done, is to get a Chromecast. Now I can browse Plex on my iPad or Android phone and cast to the TV. It works for YouTube too, allowing a better YouTube browsing experience than the TV's app has.