Current factions are anti-lore bs
I would split it into
- Undead of Undercity
- Scourge
- Trolls (zandalari top dog)
- Orcs+Dark spear+taurens
- Goblins
- Night elves
- Other elves
- Kul Tiras with remains of theramore
- Dalaran
- Stormwind+gilneas
- Other human kingdoms
- Dwarves+gnomes
- Insectoids
And make some factions neutral/friendly on start between themselves:6-12
Universally neutral: 5,9
Universally hostile: 13,2
And then you as a player can either work up or destroy your relationship with every fraction by doing PvP/PVE content, while the general inter-fraction relations act as multiplier.
Like if your fraction is in good place story-wise with another faction, you gain rep faster loose rep slower. If the fractions are at war, you gain rep slowly, loose rep very fast