As a fan of Kipchoge, I support this development. And Kiptum is not at fault. He wanted to race Berlin for a chance to break the world record, not necessarily race Kipchoge. Kipchoge on the other hand is a "big" boy and therefore calls all the shots. When he decided he is doing Berlin, organizers have no choice but have him in since as the defending champion, he is the #1 invitee. He commands a huge appearance fee, leaving only so little which cannot satisfy a huge star like Kiptum. Kiptum should get a huge appearance fee in Valencia since he is defending champion and course record holder
Why I support this( as Kipchoge's fan) is because Kipchoge's #1 priority right now in his career is to defend his Olympic title in Paris next year. Berlin therefore serves for him to bounce back from the disappointment in Boston this year. He will not want another "injury" ( defeat) and that is why he is avoiding tough competition. So we do not expect a seriously fast time. He will be out there to just test himself. Maybe a 2:03 or 2:04.
On Kiptum, the running world already knows he is the new kid on the block. He does not need to race Kipchoge because he has already shown he is better than him and would have broken the world record if not for poor tactics from his inexperience. Career- wise, it is unlikely anyone will ever beat Kipchoge ( over 10 years of complete dominance).