far be it from me to assign any limits to God's generosity, or to assume that He cannot do what He means to do Who's asking you to? No one said there were limits to God's generosity.
And He can do whatever He wants.
If God can do whatever He wants, why is it so hard to entertain the possibility that He created Mary sinless, so as to be the perfect vessel for His Son, then desiring that she who bore Jesus not be corrupted in death, took her, bodily, to Him upon her death?
I'm not asking for you to believe it, only to not consider it a 'mere fancy', or some sort of lunacy or heresy, when it is entirely possible.