I think that the idea behind the world bosses was a good one. I like that Funcom trying to generate some new content - which it certainly has...
However, I have to tell you this has been one of the most infuriating quests I have ever done. I think that while it was well intended, some changes need to be made to it in order for people to want to continue to do this all year round.
The first dragon (Black Dragon), was not that bad. It spawned in two spots and was pretty manageable getting it done on all toons, if you kept a timer going. The only feedback I would have here is to make the rewards token based so people can actually get what they want (rather than kill the dragon over and over in hopes for what they want). For example, I have one guildie that's full T4. All she wants is the dragon pet. She kept getting T2 gear / weapons over and over - which are totally useless to her. Because the pet didn't drop for her, shes going to miss out on this for the rest of the year (unless its offered again)
This second world boss though... The Yeti. Has four spawn points. This is completely unmanageable. By the time you actually get to the instance where the boss is, its full. The spawn points are in totally inconvenient places from each other, so its not like you can zone in and wait in one spot. When you have 12 toons - this is extremely irritating. For example, I FINALLY got into an instance where the spawn was, got kicked because the lag was so bad, and couldn't get back in. As this took me several days on just the dragon with 2 spawn points for all 12 toons, I'm fearing this is going to take me much longer now that there's four. Its so daunting that right now I don't even want to complete them.
I have some suggestions - aside from making the loot token based (I hear the groans now about it being a grind - but honestly, how is it NOT a grind now?), I think the bosses should also be spawn-able based on a quest. Put a lock out on them, if you need to (like maybe just an hour cool down). This way folks can spawn the dragon when they want to, get their stuff done, and go on their merry way (just like a raid)
Anyway - again, I do feel this is a good idea. It just needs to be tweaked a little based on how this is playing out now that's its implemented. This kind of stuff happens - you cant anticipate every little thing
Please, just consider this for the sanity of your players.