Hello Sabrina,
I enjoyed your post. I wanted to add that I agree that future interests are indeed a complicated aspect of property law. I believe that when a property owner has the right and ability to grant future interests, that right adds value to the concept of owning property. When considering the bundle of rights associated with property ownership, [1] I notice how the concept of a future interest supports these rights. Specifically, when considering the right to control the property and the right to dispose of the property, [2] the ability to grant a future interest allows the transferor to dictate the terms of how the property is disposed of as well as to impose conditions on how the transferee may occupy and enjoy the property. Thus, when we look at for instance, the reversion, [3] the property owner exercises his right of control and disposition when he transfers the property. Yet, because the bundle of rights also includes the right of enjoyment, the right to grant a future interest is also supported by the right of enjoyment in that the owner chooses to enjoy his use of the property by granting a smaller estate than his own to the transferee while retaining a future interest in the property to be exercised when he decides to enjoy his property in a different manor.
[1] James Kimmons, What Are Your Real Estate Ownership Rights? The Balance, https://www.thebalance.com/what-is-the-bundle-of-legal-rights-of-a-real-estate-owner-2866918 (last visited Feb 18, 2018).
[2] Id.
[3] John G. Sprankling, Understanding property law (2000).