The key to getting more people to DM is probably to make DMing more fun. Lightening the cognitive load is one way to help that.
The one area where I really think DM fun could be improved is in combat. In 5e combat the DM is basically putting on a performance where the monsters pretend to put up a fight, since if the DM tries too hard to win then it's likely to end in a campaign ending TPK. If the game was set up to allow the PCs to lose a combat without necessarily being wiped out, combat could also be challenging and fun for the DM.