Let's talk about this.
Ambush->Soul Harvest(or Soul Tether) used to be the only way you could burst someone down in PvP as a NB (outside bow openers).
I feel that even with Ambush becoming stamina based, people won't be encouraged to use melee stamina builds in PvP if their burst damage (and any chance of killing a dmg shield/heal spammer) is gone.
This will cause people to just stick to their bow openers, instead of trying out melee builds, or causes them to slot dmg shields & heals in order to survive in PvP, which leads to even less diverse PvP than what we currently have.
In my opinion, Ambush should at the very least give the Major Berserk buff (instead of Minor), especially considering it only affects the attack following Ambush.
Discuss.