Greek gods are great and interesting and you even managed to fit Eris into the game (+10 points to KI), but there's nowhere near as much as there could be. Let's start with the gods. Of the main gods we can name:
Athena Battle Sight Apollo Bright One Artemis New Moon Hephaestus Coppersmith Ares Savage Spear Zeus Sky Father Hermes Winged Wayfarer Poseidon Earth Shaker Hades the Unseen
That's 9 out of about 14 main gods. Not named are Hera, Demeter, Hestia, Aphrodite & Dionysus. We have an Aphrodite in Darkmoor though, so how about the others? Three main sisters and a party god were the ones you left out? Well I want more from Aquila and not a different game. We've fought the three sons of Cronus, it's about time Rhea and her daughters teach their brothers who's boss.
So that Gate with the dragon (Ladon) in it? We should definitely become Hercules for a while, or at least help him with his labours. We could go in there, fight a Nemean Lion and face off with Hera Peacock Crown or whatever before leaving there with some regal attire and staves for days (Seriously, on my I have 3 Ares Spears with thaumaturge). This could be about level 40/50.
Next comes Demeter, who... Didn't really do much. I'm not sure about this, but lots of new seeds and farm-related pets too. This could be either level 60/80.
Finally Hestia. I'm thinking Darkmoor+Tartarus*10,000. Crazy mental boss health, new rare loot and spells; but less cheats. On the wiki, you can't read all the cheats for a Darkmoor boss without scrolling; that's overkill. But still make Hestia and her sisters cheat, just tone the cheats down and add health. Teach that Tempest can't kill everything 1-shot.
That's my vague plan of things, but secret bosses? For Hera, I'm not sure; maybe have her daughters? Imagine fighting Hebe (Youth), Enyo (War), Eris (Discord) & Eileithyia or Angelos (Childbirth or Underworld?). Lots of cheats and Hebe healing. Demeter could have Dionysus (And his psychotic Maenad partyers) or Gaia (Killing the Earth sounds hard). Lastly for Hestia, Rhea to rival Cronus. Remember when I said remove the cheats for the Hestia/Hera/Demeter fight? Move them to Rhea, up the health and give her drops that make Darkmoor cry.
So what do you think? This is a very tired idea, so this was probably very whimsical; but don't forget to leave your own ideas in a reply. Goodbye!
To start my response off I am going to let you know they never even referenced Dionysus because what his main power was, is a little (way) innoprpriate for a 10+ game. As for Artemis NewMoon they never I actually showed her in person just spoke about her and showed you some artwork so it would be cool if we got to meet her properly. As for content in between Olympus and Atlantea that would be nice because that is a pretty big gap in levels. I actually kind of like this post because I love Greek mythology and it would be cool to see some Aquila expantions because I feel that now with the AMAZING darkmoore gear wizards skip hades and just wait out the 10 level difference with waterworks gear so I want there to be a reason the go back to Aquila.
I have 3 
Ares Spears with thaumaturge). This could be about level 40/50.
that Tempest can't kill everything 1-shot.