You can have a very well roleplayed character who is also pk intensive. The two are far from mutually exclusive.

But, I could see the advantage of a simple role that allows for a lot of fights if you are interested in focusing on learning pk.

Kruuank stands out to me as a great example of a pk learning character who was also solid rp wise.

I think the key to learning to player kill is finding a role that grabs you enough that you won't rage delete, and then learning from your defeats. Also, not becoming dependant on any other characters helps.