Samsung has released a major update to its WatchON app, the one that has been available for devices prior to the Galaxy S5. Chief among the changes is support for more IR devices, which should make more devices compatible with the app. There's also support for new countries, an improved user interface, and also improvements to overall performance. We're still not sure when (and if) the newer WatchON app found on the Galaxy S5 will make its way to existing devices, but for now, the latest update should do the trick to offer a better experience than before.
Download the update from the Play Store or from Samsung Apps.