Well, the issues that I have had with immortal elves are memory, family/marital structure and ennui. Immortal elves pose the problem for if they are that old it makes lost civilizations and great secrets of the past difficult. This is when their negative twenty to Self-discipline comes handy most are just too distracted and flighty to focus. I really play up on that the average Elf has stats from 40 – 60 and they would have a self-discipline bonus of negative twenty. Their racial bonuses represent the average stat bonuses for the race. The average core rules Elf has a bonus of five for memory. On a purely percentile basis, it is arguable that they only remember five percent more than the average human. So, they are very undisciplined and really don’t remember much more than other races limiting how much information that they have. Add in a few quirky social limitations: Isolated communities, coming form other realms (plans), and the issue of memory for me is solved.
In modern times, nearly fifty percent of all American marriages end in divorce. How many Elven marriages end in some kind of Elf divorce, especially considering their Self-discipline? In most of my campaigns, Elf marriages are fluid and ever changing. Parenting becomes a community based commitment and duty. This causes societal diffusion and isolation with no strong family unit. While it may endear a greater sense of racial and community identity, it would weaken the society as a whole.
In my current game, ennui is the secret that Elves do not talk about with outsiders. In this game, I have no dark Elves, but the Elves warn their young, “Fear the Elf with no lust for life! For with those all deeds are possible.†How does an immortal entertain himself for millennia without sinking into depravity as a diversion. The great and powerful evils are ancient bored Elves.