That's an interesting idea, but I think that leaving them separate would be in the best interests of the universities. The disadvantages you listed are precisely why it works so well separately. As prestigious as MIT is, it isn't really an Ivy League school. It is a nerdfest (which I say with the utmost reverence). Not to mention it would also, in some ways, end Harvard and MIT, both of which have incredible legacies and accomplishments. I think that they should remain separate. However, I think that they should strengthen their ties and collaborations. Perhaps allow MIT students to use Harvard's library or other similar measures?