The dock seems only for transmiting the image for tv and for some more disk space(where you can plug other HDD).
I hope is wii U like power, and in the price range of 150 to 180$. Running zelda BotW like visuals and having pokemon, monster hunter and so on is more than enough for a handheld.
BTW Id miss FFXV and GTAVI, but NX can work better as a cheap handheld.