it won't be mandatory, dat would just be silly
you still have creative mode and peaceful
oh and there already is a "mandatory feature that destroys builds"
it's called a creeper
I covered creepers by saying that there won't be a largescale thing. Creepers do minor damage.
And forget you, I like to have mobs in my world I play on normal. I enjoy skeletons, zombles, and creepers (enderman are dumb) and do not want to lose them.
I should not be forced to risk losing everything that I've worked hard to build just because a red moon rises in the sky and releases ghasts that blow everything up.
Notice I said "worked hard to build", creative mode isn't working hard. I like to work hard on my builds because it gives me the satisfaction of knowing I accomplished something through hard work.