"Players will not automatically recover HP and MP when incurring enmity."

WILL NOT recover HP and MP. It leaves room for no exceptions. This makes long fights difficult. Difficulty is not really a bad thing but this severely curbs people trying to kill things with fewer members which has always been a fun challenge. As a healer you'll always have enmity and mp goes down fast as a healer.

"Party Size
Each additional member in the party reduces the amount of experience points yielded. Although the reduction is greater than before, it will be offset by the bonuses granted by EXP chains and linking."

How are we going to take advantage of this if we can't regenerate mp?

"HP and MP will automatically recover only while the player is stationary, regardless of whether or not he/she is engaged in battle."

This does mean that if you don't actually participate in battle you can regenerate mp while your other party members fight. This may work in a chain party set up, but an emergency heal will terminate your regeneration. But since you are already being required to stay still why not add a /rest command of some sort. It doesn't have to have the time consuming animation it had in FFXI, maybe something short and small, a change in stance that you can instantly walk out of.