"...I think he's sticking with Ducati for now since that's his only option..."
As he said in the interview: Ducati left him no other choice (based on the amount of money they threw at him). Gresini was there, but Ducati had larger saddlebags.
Ben feels he has unfinished business in MGP. I think he feels the tour at Yamaha was a blemish on his reputation, and I don't think he feels the problem was all his. Yes, he admits he had some problems getting the corner speed that JL had, but I believe that he would have eventually gotten there if the bike had held up. He was awful fast at times, but cooked his tires and faded every time. That is just part of the learning curve with every series. In WSBK his bike was reliable, and familiar, and he only had to learn how the tires behaved. He adapted quickly and pummeled everyone into submission. If you can't get the laps in, you can't learn.