Science wrote:

Why would God give us the ability to choose evil when he's perfectly capable of excluding that option from us? After all, won't we still have freewill in heaven, yet won't be capable committing evil acts? Why couldn't God just have created us in this way to begin with? 

I think God could create humans already enjoying the Beatific Vision. And then, you are right, they would not be able to turn from it. For Catholics and some other Christians, there is also the example of Mary; God created Mary without the stain of original sin such that she could not sin, yet we think that Mary was free. Why shouldn't God just create all humans like Mary?

Because of those two cases I'm not so sure I find the free will defense compatible with Christianity.

I think that there are unique forms of value in redemption (e.g., Luke 15:7), even in resistance to temptation, patient suffering, sacrifice (the crucifixion), etc. That is really the "stuff" of religion.

That isn't to say that a world in which there is a Fall and a Redemption is a better world than one in which humans are created immediately enjoying the Beatific Vision. It is just a different world; there's obviously much that is good in the latter, but those goods are not fungible with the goods in the former, and thus God has a reason to create the former. (He also, I presume, has a reason to create the latter, though he didn't.)