Different materials (armor, metal, cloth, leather, fur, hair, flesh, bone, gore) are different to paint; Death Guard don't seem like they'd specifically be harder, but if you're not doing drybrushing or using washes or inks or something it might be rough.

For the Death Guard, try posting pics of some of the models you painted that you're not happy with, asking for advice. If some changes to the colors or techniques would make painting easier or give a better result, that'll be something you can also use on different models.

To go away from gory and toward armor, vanilla marines, Tau, Wraithguard are a few options. Whatever you go with, there is going to be some amount of detailed sculpting on the models, there's not much getting away from that. Necrons seem to have a fair amount of detail, but treating it as metal instead of gore might be a different experience for you.