Team Attack option
 

I suggest that there should be an option that turns Team Attacking off, allowing only one person to attack. Turning it on will enable team attack and you can fight in a group. But changing it off/on will take an entire minute to prevent "exp hoggers" killing their monsters and taking other's.

This is my first idea, I don't know if it has been suggested before. Hope you like it.

The EXP/Rep sharing subject has been a topic of discussion before. (Please Oh Please.. not here)

Although I dont think it's likely given the scope of the game, but that might be one idea to consider.
Assuming a player would engage a mob, and then have control wether he/she, or his/her crew, and/or others could participate.

This could create circumstances surrounding who has the right to horde a mob all to themselves since they could now theoretically lock out all others from attacking the mob they engaged.