The original epic rules are no more broken or dysfunctional than the core books.
The original epic rules are found in the DMG (p.206-210), and are quite simple, easy to understand, and fully playable.
The problem? Most people don't know they exist.
Epic rules have existed for most editions of D&D (pretty much ever since Mordenkainen reached level 20 and Gygax didn't want to stop playing the character...).
The Epic Level Handbook should have been 3rd edition's expansion of the basic epic rules given in the DMG. Oddly enough, even though the ELH actually references previous edition's epic rules (notably the epic spell seed rules which were inspired from the High Level Play book of yore), it doesn't seem to reference the DMG epic rules at all. As such, since the DMG is the primary source, anything which contradicts it can be freely ignored.
What then causes the bad reputation? Most people cite the rule set as the main problem. However most people are wrong, despite the admittedly wonky rule set. The real problem is that almost everyone is not following the pattern the game assumes that you are doing.
When this game assumed pattern is not followed, gameplay runs into problems. Part of the problem is that the game itself never tells you what that pattern is, explicitly. You're just supposed to know, or figure it out.
Dungeons and Dragons has some hidden assumptions built into the earliest versions of the game, which have been carried forward into almost every edition of the game since. These hidden aspects trip up groups time and again, because it's supposed to be a game of freedom and imagination, right?
So let's examine some of these assumptions.
- Your players are using the dragon's four basic food groups as characters: fighter, thief, priest, and mage. (Though we find more politically correct titles these days, and note they don't include the horses. Poor horses.)
- You have four players.
- You are keeping track of weight and encumbrance, light sources out lack thereof, and food supplies.
And so forth.
That's great, but what about epic?
So, with regards to epic, the game has the following assumption built in:
at low level you are playing a small group tactical game.
at mid levels, you are naturally transitioning away from a small group tactical game to a large group tactical game plus simple strategic elements.
at high levels, you are no longer playing a tactical game, you have switched completely to a strategic game eighth political elements where your characters are ruling over many, possibly running a country or something.
at epic levels, you are playing a political game, wandering the planes, and creating myths and legends, eventually either dying, retiring, or becoming a god... at which point congrats, you have won the game, time to retire your character and start another campaign and do it all over again.
The problem starts when almost every gaming group out there fails to transition away from a small group tactical format, unsurprisingly enough at or around level 6. (E6, anyone? )
Failing to follow this built in assumption causes the game mid to high level problems, let alone epic. Most groups crash and burn long before epic.
So, in short, the game sneakily assumes that you are playing a certain way. And when (almost everyone) doesn't play that way, the rules don't cover the results very well, which yield increasingly severe issues over time and levels.
These failures are blamed on the Epic Level Handbook version of the rules (which, again, are pretty wonky and are worthy of criticism), much online analysis is had, and the bad reputation is writ in stone.
The easiest solution is to follow the original DMG version of the epic rules.