Interestingly, it seems that it's easier to accept magic and dragons as believable than some changes in human nature. Perhaps it's generally easier to accept big differences to the real world, or perhaps it's because we intrinsically know humans better than we know the laws of physics.
That doesn't mean one can't or shouldn't try to portray a world that's different regarding humans. It just means that people are more likely to find such a world 'unrealistic' than a world with dragons.
Don't underestimate the impact of momentary distractions. Even if your comic was just funny (of course, it's much more than that), making people laugh is worth a lot, too.