It's about time something was done towards this quest. The guideline for my posts willbe the questions you mentioned:
Are there problems we haven't mentioned yet?
Most of the problems have been pointed out, but what I found to be ignored was the gap between the hardness of a task. I mean, a level 90 couldn't possibly think about doing a Sea Serpent task. There should be a rank, as other players already mentioned for players between Levels 90 and 130. Also, team hunting should be possible in a way that players with shared exp could get a kill. This would prevent abuses, and at the same time would make tasks like the Behemoth one to be possible.
Should the quest be completely redesigned or just adjusted, in your opinion?
The concept of the quest is absolutly fine, as everyone pointed out, it just needs to be adjusted.
Which level ranges should be covered?
As I said on the first question, just the level range between 90 and 130 is missing.
Which would be appropriate monsters for each range?
So far the monsters are pretty fine on the lower ranges. For the new range, I'd say Giant Spiders and Quaras should be bumped up there, also for this range, High Class Lizards, Brimstone Bugs, Bog Raiders and Undead Gladiators could defenetly be added.
As for the Level 130 and on, not only the 4 tasks we already do have, but Drakens, Warlocs, Demonic Creatures (Yes, in general), Dragon Lords, Frost Dragons...
How many would you suggest for each task?
For the Level Range of 90~130, around 400 kills would be ok. As for the tasks of the Levels 130 and over, a reducion is more than needed, from 2000 to 600~700.
How many points would you suggest for that?
The point system now is ok, for the new range, 2 points for each task, and 1 for the ones with boss would be fine.
And actually, should the ranking system and the associated rewards stay as they are?
No problems with that.
What do you think about the one-time bosses and the outfit items you can gain?
This is absolutly awesome, it actually gave a chance for players to actually make some addons, intead of camping a respawn forever.
Thoughts about the Demon Oak reward?
I find them to be actually, useless. The Rainbow Shield requires to be enchanted over and over for being usefull, the Demon Legs is worse than my Dwarven Legs, and the Spellbook and the Crossbow are Inquisition Rewards, so, they are pretty useless. Better itens should be available. I'd put a better Crossbow for Paladins, since the best weapon for them is the Warsinger Bow with Onyx Arrows, which makes the Infernal Bolts pretty useless, an ultimate weapon for Knights, like the Solar Axe, The Epiphany or The Dark Trinity Mace, as for mages, how about a better Spellbook? One with more Defense and +4 Magic Level?
What about the players that have put a lot of effort in this quest? How could we ensure an adequate compensation if we don't know who has done which task how many times? Or should we just ignore this and redo everything?
I would suffer a bit from the changes as well, but I belive this couldn't be helped, once this quest have been badly thought from start. For instance, the ones who have completed the Demon Oak should be able to change the reward, possibly by handing out their former reward and then obtaining a new one.