I think given the context of the discussion that the second and subsequent Honda riders should fall into similar places in the field as the second and subsequent Ducati riders from 2007 onwards.
The fact that in 2007 when Casey arrived at Ducati to the fatherly advice of Loris Caparossi to take it easy because it wasn't an easy ride (and then went on to blitz the field) demonstrates the futility of that argument. The second (and subsequent) Ducati riders have always struggled with the bike. The 2007 bike was built to an engineering ideal and only one rider has been able to deal with it. It was never built to Casey,
You and I both know that in 2007 the "but for" rule got a great pummeling. But for Casey it was a Suzuki at best. But for Casey it wasn't a winning bike. But for Casey there would still be two tyre manufacturers involved in motogp and so on and so forth. "But for" evened out the field to the point where Rossi was shamed by his team mate (the greatest sin of motorcycle racing).
In 2007 that was a bike built for someone else and they paid peanuts, got Stoner and the rest is history. at that time there was not a Stoner built bike and there hasn't been from then on. To link Ducati's fortunes to the performance of other riders (other than Stoner) is blown out of the water by the 2007 racing year. As soon as Stoner's scaphoid problem arose, then his mystery illness (food allergies) they offered Lorenzo double the money.
That is what Ducati thought of Casey and his input.
the reasons as to why Loris couldn't adapt to the GP07 as well as Casey are far more complicated than most think, Electronically complicated, lets face it Rossi is the only rider from the 'Old School' to ever successfully adapt to the 800's. And the Suzuki was actually quite good in 2007 so to say it was a Suzuki isn't too bad, certainly better than Nickys Honda!
Whilst the gp07 wasn't built for Casey, it was subsequently modified around him after 2007, and when the others caught up in 2008 the pressure mounted and answers could not be found. I believe after San Marino 2008 serious thought from Ducati and input was needed from Casey to address his front end issues, if that input was given then it obviously didn't solve much with the front end issues plaguing them for 2 seasons after, and still. No doubt Bridgestones lesser efforts in 2008-09-present also didn't help the Desmos development either.
I recall Casey's comments after Brno and Misano 2008, 'We did the same thing as the lap before, and just lost the front'. He didn't know then what was going wrong, either did Ducati obviously. IMO Ducati, coupled with their arrogance after 2007, were lulled into a false sense of security with Stoners very dynamic performances, especially when he blitzed the field on occasion, even after Laguna 2008. No doubt they felt that his illness impaired 2009 considerably and it is fair to say that they have made several large changes to the bike from 2007 up until late 2009 and with feedback also from Nicky- the biggest was the introduction of the big-bang in 2010.
Their lack of progress in 2010 with a healthy Stoner and Nicky is most puzzling, for from round 1 they knew that Casey's issues with the front end hadn't gone away, some feel that Ducati never did anything about Casey's input, however well publicized efforts well into the night even after they won the Aragon GP is probably just a taste of the efforts that were going in to trying to fix the Ducati for Stoner, to think they would be paying their no 1 World championship winning rider all that money and not listening to his feedback is absurd. Casey has ridden the Desmo 800 for 4 years and has provided twice as much data (4 times as much at the sharp end!) as any other rider for Ducati on their 800.
In saying that, Casey has admitted that he signed with Honda very early in 2010, many also believe that he wasn't on 'it' as much after this, it is very obvious now with their current predicament that Ducati weren't either........Stoner has been saved by Mr H. The jury is still out on Ducati's redemption......