For me this is a major concern due to the fact that when using AppleTV and a steelseries Nimbus game controller there is no way to open up my hirelings inventory. Which makes the game unplayable on the Apple TV unless you use the Apple remote. In my opinion that is not an option . I don't think there's any action on this controller that maps to R3. this is the game controller that is sold by Apple for Apple TV.
When playing on the iPad or the iPhone this isn't an issue since you can use the touchscreen to open up the inventory.
On a positive note this game controller absolutely rocks for playing DQ on IOS devices. Don't quote me but I think this game controller is also compatible for the android devices