5e Epic Classes (levels 21-30)

[Giant2005]

The Barbarian epic levels seem far too powerful compared to the other martial classes and I'm not sure why you chose to ignore the standard Rage damage progression for epic levels but keep the standard progressions for every other class's abilities.
The Monk on the other hand seems far too weak comparatively and essentially gain nothing of value at all but a +4 DC to Stunning Strike. At the very least you could give them something similar to the Sorcerer's unlimited Sorcery Points feature but for Ki. Something to keep their damage relevant next to the other martials wouldn't go astray either.
Rogues seem like they gain too little but that could be simply because they are listed directly after the Barbarian who gains too much. The one thing that really bothers me about your Rogue epic levels is the fact that the only abilities of worth they get are all limited used items that refresh on a short or long rest which simply isn't something that should be happening to the Rogue - Rogues are supposed to be energizer bunnies that don't use a recharge mechanic. Giving them nothign but rechargeable abilities goes against their design.
The Fighter's ability "Improved Combat Reflexes" needs rewriting. Even if they can make unlimited attacks of opportunity, they are still only limited to one reaction per round which means the ability would do nothing. Just change it to "Attacks of Opportunity no longer use your Reaction" if the intention is for unlimited AoOs but limited Reactions. If the intention is unlimited Reactions of any variety, just say so specifically. Also giving the Fighter an extra ASI is really cruel in Epic Levels considering everyone else gets something actually epic rather than just a rehash of the more mundane abilities. I'd replace the first of the Fighter's 3 ASIs with an ability that allows any permanent ability increases after that level bypass the normal ability limit of 20, so their next two ASIs can bypass the cap and give them something a little more unique.
I'm not really sure what exactly the Warlock ability "Additional Boon" is supposed to do. The Empowered Boons ability buffs the pact choice of the Warlock and considering they only have one pact, a second buff that applies to a pact they don't have is useless. Is it supposed to be giving them a second pact? If not I don't understand what it is supposed to be doing at all...