This is kind of a wise list from my ideas about Titan quest 2 from years ago. I hope I could be of help for one of the greatest ARPGs ever.
1. Player Customization : First by choosing a faction. Hellenic - Egyptian - Orient - Norse. Then when choosing a faction you'll start at different locations. For example if you choose Hellenic you'll start somewhere in Hellas (aka Greece) if Egypt somewhere in Egypt , and so on.
After that when you have chosen a faction you get to choose race. Example :
Faction : Hellenic - Race : Human or Monster : Hoplite - Satyr - Centaur - Minotaur.
Female Race : Human  / Monster : Amazon - Maenad - Gorgon - Harpy (wings on her back).
Faction : Egypt - Race : Human/Monster : Medjay - Jackalman - Reptilian - Scorpos.
Female Race : Human - Dune Raider - Sandwraith - Desert Hag (wings on her back).
Faction Norse - Race: Human Berserker - Light Elf - Dark Elf- Dwarf - Troll.
Faction Orient - Race: Human - TigerMan- Dragon.
And so on.
Then a little facial look facial hair color and general characteristics would be a nice touch as well.

2. Skill list could be different for every faction .
Example. : For the Hellenic it could be like the Star system on the Milky Way.
For Egypt hieroglyphics on a pyramid.
For Orient it could be the sky on clouds or something to do with the element's.
For Norse branches spreading out on Yggdrasil.
And each faction can have different kind of skill sets (some will be similar) and They could have some kind of connection with each factions culture.

3. A good idea would be like maybe finding temples of the Gods and giving favor to those who will benefit you depending on what kind of built the player is making. And they could reward you with something special for every shrine or temple you find.
And maybe help you in battle like we see in the Epic Poems of the Trojan war.

4. Epic - Legendary Items. It would be nice instead of just depending on luck to find them  to be able to craft them as well.