The higher the difficulty the better the drops but the stronger the monsters. THIS WOULDN"T CHANGE THE PLAYER AT ALL. (Keeping them the same in PvP). This is how it would work for every 1 point increase on the difficulty slider every monster gets +2% Health, Energy, and Damage dealt (Possible also increasing the chance to use skills like enchant removal and such).
The drop rate should also increase by .2% for every notch the difficulty is increased.
This would work like this: A Hydra has a 1% chance to drop a crystalline sword on normal difficulty, on 100 difficulty (the max) the hydra has a 10% chance to drop the same crystalline sword. The drop rate would also be lowered so that at 0 difficulty NOTHING at all drops. No materials. No gold. NO nothing. But you would now be able to pwn those pesky mursatt

XP should also be increased or decreased by the same amount. I.E. at 0 difficulty nothing gives you xp but at 100 difficulty you gain xp*1.1.
To stop a person being dragged through a harder difficulty than they can play the instance is loaded based on the LOWEST DIFFICULTY SETTING IN THE PARTY. Say that 7 people have the difficulty set to 100 and 1 person has it at 75, the whole instance is now set to the 75 difficulty level. A persons current difficulty level should be added next to their name so that there are no mistakes in forming a party.
The difficulty level should only be changeable in towns/outposts and not during an instance.
As I already stated on your first run through the game you have to play at the default setting. This is to teach people the basics and so that they know the story.
To stop people from abusing this by putting the difficulty to 0 to complete a quest this should be added: A quest can only be completed if your difficulty is at least 45. Yes this is 5 points lower than the default but what happens when you just can't find a good group for villainy and need to use henchmen? The easier difficulty compensates for the bad PUGS. Could this be abused slightly? Yes, but most of this game can be slightly abused (look at the griffon run video for proof) stuff like that was probably never intended by ANet and by comparison abusing this would be a minor abuse.
Please post either constructive criticism, suggestions for improving this idea, possible flaws that you see, or your support and why you support the idea. Explain all your posts: No "This idea sucks." Explain why the idea sucks. Please try to stay on-topic and I will ask a mod t o delete the off-topic posts as I am tired of all the suggestion threads getting filled with off-topic drivel.
BTW Here is another thread were this idea was partially brought up and it has a little discussion about it in their. http://www.guildwarsguru.com/forum/s...578#post240578
EDIT: Look at my third post on the page before commenting.