Played Harbinger for about an hour on golem - feels really boring. Got to 36k cdps. Power build is just straight up not good. Only 22k dps for me. Don't know why Anet pushes this duality where there is non. You can probably drop all the top row traits for something new and condi or support oriented. Or buff power.
Elixirs are just buffs and there to get blight, nothing more, nothing interactive about them whatsoever. Don't know if it's a bug or not but blight from elixirs and blight from shroud is different. Each has it's own duration and sometimes blight from elixirs expires in shroud and shroud stops giving any blight for 5-10 seconds. Maybe it should stack in duration also or maybe it should start it's duration once and then only stack in intensity.
The rotation felt really bland. You use elixirs, plaguelands, blood is power, dagger 4, pistol 2, shroud 2 3 times, then repeat. In shroud only shroud 2 is useful for dps purposes. I think shroud 1 should have combo, maybe it will be more fun to watch. Maybe shroud 5 should have some conditions on it.
Overall I feel scourge is much better and fun at this. Why handicap yourself to deal 5-7k more dps when you can also support your group with barrier? Even though -50% HP in PvE is a non issue, because dodge.
On the PvP side though - I really like it. Mobility is awesome! Damage is a bit too much, I think (for sPvP). Still need to learn to play it though but at least it's fun. Feels like it can be new roamer type of spec. On par with mesmer or thief.
Though not without some issues - Life force generation feels weak without Elixir of Promise. Mainly because shroud just gets wasted by chip damage. Maybe it should not be using % of shroud and rather use the exact amount to heal? Pistol 3 cast time feels too long. It's easy to interrupt, yes. Maybe not 3/4 cast time but 1/2?
Also harbinger has no chill - so no interactions with many chill traits in core, feels weird.