Bounty system should either have you collect clues about exactly where the boss is and/or boss scaling to the num of players in the area. OR it could be instanced when you reach the area, similar to the "naked man on the waterfall" quest
Its bad when a lot of players search for a bounty to pass by its location 100 tumes because someone else already killed it. Very frustrating
Also i found the bounties to be very easy to solo, could make the fight a little bit harder and interesting.
Dynamic Events is a very cool idea, but I think it needs more variety. Random freeing of NPCs and stopping rituals by killing 3 mobs isn't it. Maybe Dynamic Events need to have something to do with the "theme" of the area. Take some notes for Guild Wars 2 , noone does this better.
Also I think level-scaling in lower level areas will highlight this feature and the world even more. Participating in dynamic events (especially if the gives you some reason to) on a lower level area will be more interesting and kind of fun, instead of making the areas (and the devs' work) no longer relevant as players level up.