Over the years, Blizz has introduced a lot of different magical systems tied to the various cultures.
Many of the orc clans have their own spin on their shamanism, Trolls mix loa worship into their shamanism, and the Draenei have a direct line to the Light through the Naaru. Tauren explicitly use Night elf style druidism but developed their own take on it into 'Sunwalkers' even if Blizz has shifted away from considering them sun druids despite that flavor fitting better.
But the original forms of Shamanism, Druidism, and Light worship with the tauren, nelfs, and humans have sort of fallen by the wayside over the years.
What are some ways that they could be developed and given some depth?