Skylanders Super Chargers released in 2014 on current and last gen consoles, as well as iOS devices. Acitvision released the same screen shots of the game for multiple platforms, which makes comparisons like this easier. For iOS, they supported the iPad 3rd gen (2012), so it obviously could look better if it was optimized for the iPad Air (2013) or iPad Air 2 (2014).
In my opinion, the current gen version looks the best (especially if you view it at full 1080 resolution), followed by the last gen consoles, followed by tablets.
To answer the OP, I don't see any mobile device being more powerful than a PS4 or XBox One in 2017.
Unless you consider the PlayBook 4 a mobile device (although it doesn't run on a battery, but it does have an ARM processor inside, as does every PS4):
http://www.extremetech.com/gaming/192064-turn-your-ps4-into-a-laptop-for-1100
Also, you can play PS3 games on current mobile devices through Playstation Now, and you can Remote Play PS4 games on mobile devices, but I don't think that was ARM's line of thinking.
Images are below:
PS4
Xbox360
iPad 3rd Gen (2012)
