Speaking with the UK's Autocar, he said his team's "core task is to differentiate the design philosophy of the three brands".
Part of this desire stems from the stranglehold the company has on the South Korean market, where it accounts for 70% of all new car sales. Failure would see the Korean automotive landscape become "too homogeneous" from a design standpoint.
With Hyundai Motor Group present in almost all markets across the world, and with a range of models aimed at both developed and developing markets, Donckerwolke says the company "will not have a global design language because otherwise it’s too rigid".
Instead, there will be "unifying themes, with varying treatments" applied either by segment or region.
He also promises a "great new show car" for the Genesis marque, which will move in the direction of haute couture.
Byungchul Juh, head of design for Kia, says the brand will keep its distinctive tiger nose grille, but also transition to a "tiger face" with a "distinct version... for each segment".
Overall Kia's mission is to be "innovative, young, challenging, iconic and cool".
In his opinion the next-generation Optima will be a "first step" towards this ideal, but will "not [be] extreme but progressive".