I've had various incarnations of these characters being built since the mid 90's! Some components of these old versions still survive in these models. The main idea here is to get a balance between the look of original epic scale models and more recent depictions of the primarchs, trying to get something that will resemble the epic models but also fit in with the current CSM and daemon minature ranges
Wanted the big red fella to look like the original epic scale model but with armour on. The dreadnought torso he's stomping on will be painted in Grey Knight colours; I reckon Angron will have a bit of a grudge against them after the 1st Armageddon War!