What are the better feats for respective faction/heroes and what could be better, what could be toned down and what is completely utter garbage?

I´ll start by saying that many of the Valkyries feats are lackluster... The only thing that is really usefull is the javelin and the rest are pretty much meh... I personally go with passive, (something that grants attack and defence from hero kills, which I can´t remeber the name of), javelin and the mark of death -feat. Some could be better and some feats are completely useless (gain health out of combat -feat as an example)

Warlord, Warden, Kensei and PK I think get the best package, sincethey contribute to each heroes playstyle.