Realms I think need to be part of a metagame played between guilds and gods.
I would like to see guilds fighting for control of realms, perhaps based on how many of their number have completed them, or how many points they scored while doing so. The higher the realm level, the higher the reward.
Each realm would deliver some benefit to the controlling guild. Perhaps the demigod running the guild could use these 'points' to buy temporary bonuses for their wizards - additional exp gain, or a slow increment of forge crystals, or even a unique talisman or spell.
Within the realms as well we expect to see shrines where the gods can be worshipped or their image desecrated. This gives another reason for particular guilds to play particular realms, if a shrine to their favoured deity is located there. Worshipping at shrines will lead to 'worship points' that gods can spend to bless their followers, perhaps in a similar but more powerful way to the demigods.
We still haven't really heard from Snapshot how demigod and godly powers will work, but I kinda hope it's a bit like this. (I realise there would be an objection against anything that gave a PvP advantage based on guild rewards, so perhaps the rewards would need to be mostly non-PvP-related, such as gold, exp, bonuses in realm battles etc.)