A weird, whacky, and totally unconventional thought:
Start out with no water. Let global warming change the desert into coast. Make pollution be your friend! Let irrigation give high bonuses so the risks from tile pollution are worth the benefits from global warming. It'd be an interesting change in strategy. A deviation might be to have plains and desert equivalent to the deserts of Dune, and letting plains convert to grass while desert converts to coast (in this case, sand worms could travel on plains and desert, but not grass). Technology to bring water to Dune's surface would then be represented by pollution producing buildings. Totally whacky, eh? Nuclear weapons (crashing comets?) suddenly become really attractive...
Another, separate thought is to make spice/melange only appear in the desert, but give it a very high rate of dissappearance, and set it so that cities can't be built on desert. This would serve several purposes. First, it would make mining spice very important to the game. The mining would be very competitive, as the only way to get it (unless you were really lucky) would be to create colonies and build the roads to get there. The colony graphic could be replaced with a harvester graphic, and the worker animation with a harvester animation as well. But between worms running amok and the other factions, these spice mining operations would be very hazardous. And the concept of spice blooms and limited melange deposits would become a major game point. Besides, it would give all those workers something to do! Spice would technically be a luxury, but would also be required for advanced buildings to help represent the benefits of interstellar trade and the extreme importance of melange to the Dune universe. Perhaps also required for advanced units.
I admit to having only read the first book and immensely enjoy Dune 2 and 2000, so if I am missing something from the later books, bear that in mind. I am assuming worms as barbarians with very high stats, making them difficult to kill. (I did manage to kill a worm in Dune 2000!)
Start out with no water. Let global warming change the desert into coast. Make pollution be your friend! Let irrigation give high bonuses so the risks from tile pollution are worth the benefits from global warming. It'd be an interesting change in strategy. A deviation might be to have plains and desert equivalent to the deserts of Dune, and letting plains convert to grass while desert converts to coast (in this case, sand worms could travel on plains and desert, but not grass). Technology to bring water to Dune's surface would then be represented by pollution producing buildings. Totally whacky, eh? Nuclear weapons (crashing comets?) suddenly become really attractive...
Another, separate thought is to make spice/melange only appear in the desert, but give it a very high rate of dissappearance, and set it so that cities can't be built on desert. This would serve several purposes. First, it would make mining spice very important to the game. The mining would be very competitive, as the only way to get it (unless you were really lucky) would be to create colonies and build the roads to get there. The colony graphic could be replaced with a harvester graphic, and the worker animation with a harvester animation as well. But between worms running amok and the other factions, these spice mining operations would be very hazardous. And the concept of spice blooms and limited melange deposits would become a major game point. Besides, it would give all those workers something to do! Spice would technically be a luxury, but would also be required for advanced buildings to help represent the benefits of interstellar trade and the extreme importance of melange to the Dune universe. Perhaps also required for advanced units.
I admit to having only read the first book and immensely enjoy Dune 2 and 2000, so if I am missing something from the later books, bear that in mind. I am assuming worms as barbarians with very high stats, making them difficult to kill. (I did manage to kill a worm in Dune 2000!)