Ahhh, must've been my search parameters. But what 5thHorseman says explains why it's not been done thus far.

TL;DR To rearrange the research queue, one must delete items in the queue and reselect them. This can be made simpler What ? Just make the items draggable so you can rearrange items within the queue and this will solve all issues in a couple of short steps. Why ? Simply makes the queue easier to us...