Absolutely terrific thread.
We just recently completed an Epic campaign. We use the Forgotten Realms, and had mulitple campaigns worth of characters who were played up to 20th level, that the players could choose from. We've run about 10 campaigns in our version of the Forgotten Realms, dating back to the original boxed set coming out (so about 15 or 16 years). One of the great things about going Epic, for the first time, with this group was the opportunity to ressurrect a few of your favorite "old characters". We had a mix of 1st, 2nd, and 3rd edition campaign characters, some of which took a little converting. So, a great deal of the fun from the get-go was to get this group of the world's "legends" together, and put them into some fun and interesting new developments.
I know I'm not necessarily usual in this regard, but I have an aversion to a couple of types of plots: time travel and plane travel. I like the concept of there being other planes out there, but I don't want that to be the core plot. I don't like time travel at all, and I want the planar stuff to truly be beyond the capabilities of mortals. Including epic ones. So, putting the campaign together, I did a little field research on the FR. Will there be enough in the core supplements to challenge them? I found 164 epic level NPC's. Ok, this shouldn't be a problem. There were appoximately 65mm people identified in the main continent of the Forgotten Realms. So, just using a basic statistical model, to say that 80% of the world is a 1st level commoner, that still left 13mm who were better than 1st. Probably half of that would be above 5th level (6mm), and half that above 10th level (3mm). That's still a boatload of people. I found this to provide me with plenty of room for opportunity, challenges, and the ability to expand (without really negatively impacting the believability).
Immediately, it became evident that there were some balance concerns with the epic feats. One feat lets you instantly kill anything you hit, and another one gives you an additional +1 to hit... Hmmm. We went with it, anyway, and it seemed to work out for the most part. We used some of our experiences from playing epic in Neverwinter Nights to address things we knew would be issues. Devastating Critical, Automatic Quicken, and Improved Metamagic. This was immediately what the players were drawn towards. In addition, if players with this level of resources (GP Wealth) truly was given free reign to build or select their own magic items, it became immediately evident that there are some high end items that are overwhelming. The books that add to stats, vorpal, sunblades, ghost touch weapon and a ring of blinking, heavy fortification, Major Displacement, Spell Turning, and in the FR...items of that grant Mind Blank, such as a Cowl of Warding. In addition, anything that would grant DR/ER was always welcome. These were at the same times, must haves, and completely broken, particulalry in combination with each other.
The game was fun to play. People loved to push the story of their "legendary" retired heroes. They loved to flex their muscle and use all of their incredible powers, abilites, and items. They were able to be challenged, on a number of levels. In many instances (from 20th - 25th), it worked very well to mix in Epic only in small doses. Creatures from the MM were plenty challenging, particularly if you threw mulitple together. One of the most challenging fights the players fought was a group of dragons (I belive it was 10 dragons on 5 players, at around 24th level). Making it a 24 ECL, the dragons would be about CR18 (what would appear individually as total weaklings to the party, and their capabilities). It's safe to say it didn't end up that way, at all.
By 30th level, the party was extremely powerful. Epic villians were required, almost exclusively. That's when things really fell apart. Many of the epic villians, in order to be able to survive, were forced to rely heavily on tremendous immunities, and multiple layers of defenses. This was not only cumbersome to DM, but it also truly began to feel like the players were losing their sense of "greatness". The players were forced to spend multiple rounds just finding out what could affect a creature, then beating it senseless with whatever that was...since your ability/spell/weapon would only work 10% - 25% of the time at best anyway. We also ran out of good things to get. The players had fundamentally maxed out their character's abilities by this level, using the core Epic rules.
Some other things that were painfully missing, and much needed for our epic game:
1) A good mass combat system, I bought them all, but ended up using my own houserules to dramatically simplify and fit the campaign. At epic levels, this is certainly a must have.
2) A good resource management system at a "kingdom" or "country" level. This is really what most of the campaign was about. The interplay between the many different power brokers at work in the Realms. The give and take, the move and counter move. Etc. This really could be it's own separate game (Age of Empires), but would be insanely cool if it could work in players' abilities and actions into it.
3) Effective countermeasures...there a number of spells and abilities from 12th to 20th level, that appear, but don't have effective counter measures built into the game, but they clearly should. To name a few...blink, displacement, anti-magic shell, wall of force, time stop, commune, mordenkainen's disjunction, true sight, Greater Teleport, Shapechange, Mass Suggestion, Etherealness (Ethereal Travel), and AoE damage spells on armies. This is a list off the top of my head, I'm certain it could be expanded.
Our group did not even consider/touch epic spellcasting.
Our group does use expedited experience/level gaining.
