One of the elements of midichlorians is that it canonized the idea that one's capacity for using the Force comes from heredity and/or environment. Personally, I didn't see any issue with this, as the importance of Luke Skywalker to me always was partially due to his particularly high capability to use the Force. I'd always taken Obi-Wan and Yoda's "The Force is strong with this one," and "The Force is strong with your father, you, and your sister," to indicate that Luke and Leia had this skill due to heredity.
When discussing the issues that the prequels bring up, a common discussion point is on the heredity of Force adeptness. In the original trilogy, was skill in the Force something anyone could gain, or was it meant to be hereditary?