I would prefer to play K/P and some posts from folks here are saying that all the tanking combinations are viable - so maybe I should just do that.
There are some questions which you should have in mind:
1. Will it be less fun to play K/W instead of K/P and will this lead to "i don´t want o play anymore" ?
--> play K/P
2. Do you have a high-end-guild which burns every boss down due to good DDs and supporters?
--> play K/P (or any other tank which can deal with their aggro)
3. Is your guild not that strong and you need everything to master a dungeon?
--> you need K/W ("Authoritative Deterrence")