Haven't gone through the whole thread. So, apologies if this has been addressed.
If there is one thing that became evidently clear during Djokovic and Nadal's matches recently, specially the French, is that Djokovic needs to follow on his strokes to the net, when he pushes Nadal off the court and put away those defensive retrieved shots. So many times he allowed Nadal to get back into the rally with floaters and other easy put aways.
I was glad to see that he began to work on that in his later matches, but he is still not good enough and that overhead thing must be remedied.
So, hiring Becker makes sense to me from that aspect and in terms of grass movement. However, will their characters be compatible is a totally different story. Really, don't know about that. Tactically, I think it does make sense, though.
