Also the fact that he gets to enjoy some of the profit from sales of the game discourages him from making the game world too miserable.
It really only motivates him to be overly nice in order to keep people playing ..
Also, it depends a lot on what the game is like and how godlike being a god makes you. It could range anywhere from his presence being an amusing treat for those lucky enough to meet him, to him simply being the living equivalent of an unkillable boss monster that the other players flee on sight. Either of those are not necessarily game killers.
The first sounds less of a god and more of a fairie or something .. the last sounds like it only has the potential to destroy. Big and powerful, sure, but not really god status.
I could even see you monetizing an online game by letting players buy god-mode and building the whole game around the fact that those god-like players are a major antagonist, possibly balanced by good god players who try to maintain equilibrium.
In order to have any sanity, you'd need the price to be ludicrously high, which would just lead to rich people being gods in-game .. or limit the number of gods at any one time with a queue that you have to wait in .. but who's going to recede god mode that they paid for? :p
How about you pitch that to the Eve online community and see how they react? Surely they wouldn't mind a few space gods mixing things up ..
There's just too many possibilities to assume off the bat that this is going to be a disaster, and the possibility of failure is actually a step forward for Molyneux. His other "Novel" games like Fable are just bland and shallow applications of mechanics that have been in games for ages. This actually shows some creativity.
I'll agree he's trying something slightly different, although I still think it's probably just going to end up being silly.