After the Final Fantasy XI guild, Beyond the Limitation, tried to best the Pandemonium Warden notorious monster in a marathon 18 hour boss battle, and still failing to kill it. Square-Enix is looking to rework some boss monster fights so they don't sap player's time, energy and well being.

A news release on Final Fantasy XI's official website, PlayOnline.com, says:

It is by no means the desire of the development team to see players involved in encounters that require an excessive amount of time and effort to complete. It was for this reason that previous measures were put into practice which prohibited NMs from being held in battle for prolonged periods. In response to these events, we have determined that further alterations are required to prevent such battles from exceeding a certain predetermined length of time.

According to the news story, a patch is in the works for an early September release which will make "modifications to the degree of difficulty of Pandemonium Warden (and associated pets), Absolute Virtue (and associated pets), and Jailer of Love. The aim of these changes is to create battles where a decisive outcome may be reached within a shorter period of time. "

In my experiance with MMOs and Boss Fights in both 5 man and Raid enviroment. Anything longer than an hour is too long, though some fights may seem longer because of the strategy involved. But a boss fight which takes almost an entire day is unacceptable. I hope S-E gets this figured out so we don't have FFXI turning into one of those "see what playing games does to you" stories.