I have actually managed to build a Guardian that is good for ALL situations - ask JokerD.
15/10/20/20/5, Full knight /w Valkyrie runes.
Hits quite hard with invul + heal symbols, shouts to buff and heal, takes quite some damage before going down.
Now all I need is an ultimate skill that calls down a skyscraper sized sword onto my enemies and it completes her namesake.