I don't know. I have to say the marathon has been very easy for dibaba from the beginning, because she was was already doing half marathons while she was still on the track. In her marathon debut( London), she ran 2:20 ( that's a PR for a lot of elite women right now) and finished in 3rd place. She would have won the race had she not dropped her water bottle, which led to the Kipligats dropping her. From cross country, to the track, to the road, dibaba's progression has always been very good. I wish her sister was just as focused.
One thing Kipchoge, Bekele, and Dibaba have over Ayana is GREAT CLOSING SPEED, and great stamina. They didn't die in the last half of their races, and they ran doubles, with Bekele and Dibaba winning the double more than once. I question Ayana's stamina. Yeah, she can get out fast. We all now that, but in the half and full marathon, you have to be able to close. So let's see if she has stamina for the roads, or will she fade later on in marathons races like Tadese( and tadese was probably the 2nd to 3rd best 10000m runner on the track during Bekele's era). I wouldn't be surprised if she turns into a half marathon specialists only.
We shall see.