I think you're on to something there. People playing Cube-Engine games shouldn't be able to just edit geometry, they should have to dig for hours to get your blocks while an army of creepers blows up the rest of your work! The harder it is to use an editor, the more it builds character!
But seriously, I agree with Calinou. I don't think any Minecraft fans will be switching over any time soon. I'm friends with a couple Minecrack addicts, and from my experience their minds don't work the same way as ours. Their goal isn't to make beautiful 3d environments like most mappers here. They simply like the semi-lumberjack pleasure of conquering the virtual wilderness with long hours of hard, repetitive work among many hazards. how I understand it is:
"When you build your first hideout, you marvel at its beauty because of all the hard work it took, and you want more. Soon you start building more elaborate things, cities, empires, and collecting rare and priceless treasures. You feel invincible. Then, suddenly, you realize it's 4 in the morning, and you've just spent all your free time last week making a blocky replica of the Death Star without moving once from your chair, and you suddenly feel weak and worthless. "What about all the hard work it took to get this far?" you ask yourself. As the realization sets in that what you thought was hard work was just sedentary repeated clicking, you start to panic. You need something to console yourself that you've really done something worthwhile, so the next time one of your friends comes over you say,
"Hey, you wanna play Minecraft? It's like, one of the best games ever made. At first, it doesn't look that good, but once you give it a try you see how awesome it is."
And if you're successful, your now fully addicted friend looks up to you as the great and powerful mentor you view yourself as, and you finally feel complete. with any luck, you'll never realize that your (most likely)male bonding ritual is not a desperate struggle pitting man against the wild but a blocky distraction that takes all your time but little to no skill."
(Okay, maybe I'm exaggerating a little. But you get my point.)