Hiya.
I guess the point I was trying to make was this: My version of "Epic" would be in what the common populace would recognize the PC as being "epic". Having a Proficiency Bonus go from +6 to +9 is simply not going to be noticeable by the average commoner. It needs to have commoners go "Wow!", in stead of "Well, duh...of course he's a good fighter".
(NOTE: This is the third take on me trying to write this down...it's really hard for me to explain the feeling I'm having for what I see "epic" as being...but here it goes!)
Visual. Epic things should be noticeably visual to the average commoner. Stuff that makes a character unique, even to another equal level character of the same race and class. In this way, Epic stuff should be racially based, and also unique to the individual character based on all the stuff they did and experienced in order to get to Epic Level. Serious...and I mean
serious...DM consultation would be required. No simply choosing an ability from a list and then telling the DM "This is what I took". It's something that can't be taught or learned...it simply happens.
A Tiefling, for example, that had a penchant for fire/flame based magic who fought back the army of the Ice Jarls of Frostpeaks, who slew the monsterous Icy Arch-Demon Manzaakor, who saved the entire country of Jungleopia from the eruption of Mount Kami by quelling it's mighty liquid-fire...well, change his Resistance to fire to Immunity to fire. Also give his skin the surface look of coal, and as he gets angry or casts magic, his skin starts to look like burning coals...when he's casting more powerful magics, he is wreathed in flame (1d4 damage to those touching/grappling with him).
Epic Tasks and Epic Failures, for Little Reward. The stakes should be raised significantly with any character who hits Epic level. Gods, arch-devils, demon lords...those are the foes the epic character needs to deal with. They can not avoid them. They will be called to task by such beings on a more or less constant basis. These tasks will, at minimum, require no less than the completion of 3 impossible tasks by lunchtime. Success simply means nobody notices what almost happened (Phil the farmer drinks some tea on his front porch, Bella has to drag her blacksmith husband home from the bar...again..., life continues as normal for everyone). Failure means that
EVERYONE notices what happened (a 1,000 foot pit of chaos swallows the castle and center of town and 10,000 hell-spawn pour forth, destroying everything in a 14 mile radius). In the end, the PC might get a "Nice job! Thanks!" from the deity that tasked them with it (or the cold shoulder if he failed).
Setting Out on The Path. On that note, I think gaining XP after 20th level should be a
choice. You don't have to. You can freeze your XP as soon as you hit 20th. However, once you do decide to gain xp after 20th, you can't stop. You are set on your path to epicness...with all the good and bad stuff that goes with it. You, as an Epic-level character, pretty much accept that you are a pawn of greater powers and you have little "choice" in what you want to do. After all, it rarely ends well for Epic characters, and their lives during their "epicness" generally sucks for everyone around them. Deal with it.
Bottom Line. Guidelines for epic stuff, but virtually no hard and fast 'rules'. Noe "Epic Feats", no "Epic Skills", no "Epic Spells", etc. When you hit Epic level stuff, you've pretty much moved out of the realm of "normal rules for all the normal folks of the world". The rules change for Epic stuff. Uniqueness is the key; no cookie-cut "I take this ability" or "I have that bonus". Each and every Epic level character should be totally unique to the character and the campaign environment he grew up in. Every 'ability thing' an Epic level character has should have to be explained to a new DM or other Player...there should be no "Oh, I have X; it's on pg YY of Book Z". So I guess a book about Epic levelness would be all about guidelines and how to 'create' Epic stuff for your campaign (in case you are wondering, it should be a "DM" book...not a "Player" book).
^_^
Paul L. Ming