Hi Brightlord
Here's my two cents:
a) How should experience gained be shared among players? (friendly, range, level differences, killing blow etc)
This would depend on if you plan on implementing "parties" like in D2...If you were to implement player parties then I believe exp should be split evenly across all "eligible" party members.
Eligibility would be determined based on proximity and level.
Proximity would be a fixed distance, I would normally say "a screen away" but the screen distance varies based on resolution settings so it would be up to you to choose a fixed distance that seems acceptable.
As for level, I would choose the highest level player in the party and only make players who are within a certain level range eligible to gain exp. For example, say 6 or 7 levels. This is the only way I can think of that can't be easily "gamed" by players to powerlevel characters with higher level ones.
So when a monster is killed exp is granted to all "eligible" members of the party who killed it.
Same as in "a" for quest progress and rewards
This part would work similarly to part 'a' except there would be no proximity requirement for quest progress. One player could complete an event while his party member was in town and both players would still get quest progress. Monsters or objects that drop quest items (like the mushroom patch or the monster that drops shadowfang) should drop one item for each member of the party that opened/killed the object/monster. Once these items are turned in for quest progress, all members in the party who received credit for the quest progress should have the item removed from their inventory, so only one person will have to turn the item in.
One change I would make, however, is that quest rewards which are normally dropped on the ground should instead be placed directly into player inventory and, if full, should instead be placed directly into a special tab of the player stash reserved for quest rewards only. A simple message could appear onscreen that says something like "Spectral Elixir has been added to your inventory" or "Spectral Elixir has been added to your stash".
If a quest is completed in a game already, or a player is not "eligible" to complete a quest when their party does then the game should behave similarly to Diablo 2 where the quest log will show that the quest cannot be completed in the current game. This also applies if a monster/object that drops quest related items is looted by someone not in your party.
c) Game difficulty increase when another player joins. There could just be lame 100% more hp on monsters or something more elaborate. For example greatly increasing difficulty (and rewards) that would force roles for players in teams.
I think the way the current Monster Power level scales is an appropriate increase, have the game boost/lower difficulty equivalent to a level of Monster Power for each player that joins/leaves. I would make this effect seperate from the Monster Power system though so that players wanting more challenge could enable Monster Power on top of the difficulty increase.
d) Degree of friendly fire
As much as I hate to say it, I think friendly fire needs to be removed altogether (except for when players are hostile). Diablo 1 has levels that are far too small with many narrow corridors which would make it impossible to play together with any degree of enjoyment or efficiency. I think projectiles should pass through allies without damaging and spells should not harm allies otherwise it will be impossible for rogues/sorcerors/warriors to play together at all without being in each others way and making everything very annoying and not fun. This problem already existed in the original Diablo multiplayer, especially once the sorcerors got ahold of AoE spells.
a) Should damage players do to each other be reduced by a % value?
I think so, otherwise the game will be a giant 1-shot fest. It will have to come with testing and experience to find the right amount.
b) Since there is friend/enemy system already implemented. Should player be able to turn hostile against other while being inside dungeon or just when in town.
I think hostile should be able to toggle anywhere. If both players are in town then hostile should take effect immediately, but if one or both player(s) is in the dungeon they should be given a warning on the screen ("Player" has become hostile) and a brief time window (10 seconds or so) to react before the other player is able to damage them.
c) Is pvp content wanted? There could be many things like arena with timed auto ressurect that also prohibits drinking potions or using scrolls. Maybe even whole deathmatch mode level with auto respawn and kill counts.
Seems fun, but given the relatively small playerbase I'm not sure how much it would be used. It also seems like a ton of work to implement but I would definately try it out at least once
