Population moving could be done via a "Join city" spell available only to malakim settlers/wrokers
Or how about the ability to convert population into desert raiders by spell instead of construction if the city is in a desert?
Population moving could be done via a "Join city" spell available only to malakim settlers/wrokers
Suggestion: Add to Malakim city one commerce per number of deserts in fat cross limited by number of population.Beat me to it. I was thinking of the same thing, but with a hard cap of +5 commerce. I think your idea for a cap to the bonus is better though.
Or it could be automatic: malakim nomads randomly leaving cities as uncontrollable units, which travel to other cities to add to the population there.
On the GP theme, how about plain deserts (not flood plains or oases) contribute Great Prophet points, perhaps requiring a given civic or tech first. Or, achieving a similar result but with a more direct benefit to the city, granting a free priest for every two plain deserts in the BFC? It's reasonably simple (I say that knowing nothing about how to mod it in!), and hopefully in keeping with the overall religious theme (wise men/hermits out in the wilds etc).
My 2p.