This is intended as a homebrew replacement for the Mythic rule set in general, but it came about as a result of my looking at Wrath of the Righteous as my next big project to re-write and hopefully run. I'd be interested on any thoughts and comments, both in the context of the WotR AP and as a replacement in general.
The first complaint I had about the way Mythic was structured was that it never gave the players time to really enjoy their capstone, something that's already achingly absent from usual gameplay and had a chance to be rectified with the opportunity for Epic-level play. The second (and biggest) complaint was how cumbersome, complicated, poorly designed and poorly play-tested the Mythic rules actually were. This is an effort to correct both of those issues.
1) Rather than gaining 'Mythic' levels separately, the characters simply advance at a faster rate, effectively leveling at what would be Mythic level 1, 2, 4, 6, 8 and 10. Alternately it could just as easily be at 1, 3, 5, 7, 9 and 10. Either way, the character ends up effectively at 26th level. Classes are still capped at 20th, meaning that multi-classing or prestige classes would eventually be required. Note that the leveling above is specific to the WotR AP, and that in the general 'Epic' rules presented below there would theoretically be no upper level limit.
2)Character attributes are determined using a 25 point buy. At 4th level and every 4 levels thereafter, they gain +1 to two different attributes rather than only one. At 24th level and every 4 levels thereafter, they gain +1 to every attribute.
3) Starting at 21st level, characters are eligible to select the Mythic versions of feats, provided they meet the pre-requisites. Additionally, the character may select one of the following three options as their Epic Power (with X being equivalent to the number of levels past 20 that they've attained, i.e. at 23rd level, X = 3):
Fated Champion: As an immediate action, the character may re-roll any d20 roll they just made with a bonus of +X. This ability may be used X times/day.
Archmagus / Divine Herald: As a free action, upgrade any one spell you cast to its Mythic version. This spell does not count against your daily spell allotment. This ability may be used X times/day.
Inspirational Leader: As an immediate action, grant an ally that can see or hear you a standard action. This ability may be used X times/day.
I believe that this is an effective way to handle Epic/Mythic level characters - it keeps them from becoming so OP'ed that any challenge imaginable is still a joke, keeps the rules simple enough that it doesn't require a high degree of system mastery to enjoy and still gives players the 'feel' of being something truly special, both from the beginning and especially once they reach the post-20 era. I'd be very interested on hearing any thoughts that other players and GM's whom have played with Mythic or experimented with Epic-level rules might have about these ideas in particular.
Re: the bit about Mythic feats, that's actually still up in the air, given the fact that there won't actually be any instances of 'Mythic Power' to use with them. For now, presume that part is stricken.