Thank you for replies.
Yes, this is only a model to test the idea, but I'm not really happy with it. It looks like what a plague marine might look like at the Siege of Terra (i.e., recently corrupted), but I think it needs more...Nurgle.
Regarding the current models, I use the word ostentatious as whilst they are interesting models, I find them to be almost comical in the level of mutation and "bells and whistles". I much preferred the metal plague marines of the 3.5 codex. They looked sick, but they also looked damn sinister.
One thing that is bothering me is the colour of the power-cables on the back pack. I painted them to match the plasma generator of the plasma gun, and the eyes are the same. I intended this to be a spot colour to contrast the armour, but I think it looks almost too clean and bright. What do you guys think?
I'm going to go back to the drawing board and see what I come up with. This little guy, however, will instead be gracing my desk at work haha.