The research view already shows the queue of things to be researched in the lower left corner. It should be possible to drag-and-drop things in here, instead of forcing players to remove their entire queue just to push a single item to the front of the queue (this often happens when we have to react to changing conditions among enemies).



To make this feature easier to implement, simply pulse the queue red and do nothing if the player tries to re-order an item in a way that conflicts with technology dependencies.

I believe this has been discussed a few times already. But to reply to your question, it is simply that at the moment, any technology you research on the tree may or may not require another technology; that's the whole interdependence concept you mentioned.



Allowing to make changes in the queue by drag and dropping several items would require some dev time, which does not really seem convincing for so little comfort and such confusion as a result.