This time last year many people were discussing who was Ducatis #2, and while I will admit at the time (as well as now) I think Jack Miller is, a lot of the people I spoke with at GPs and online, Alvaro's name was constantly being brought up. and looking at the rider line up they had, Lorenzo just was not a good fit, Petrucci has always lacked consistency (and he was on a factory bike), Tito and Karel were even worse in that department.
Personally I think they should promote Miller to the Factory team, and give serious consideration to Alvaro for the open spot on the Pramac team.
If you had conversations with people within Ducati or the MotoGP paddock who felt that Alvaro would have been a good choice for a better ride, they were in direct opposition to everyone I speak with. The feeling last year was that with the arrival of Alvaro's baby, he had lost a bit of motivation to go fast. You can see that in the results, with a best of 9th as of the 8th round of the series.
Lorenzo was not a good fit, thats for sure. That relationship was done when JLo felt disrespected in the same way that Stoner felt disrespected during the lactose debacle.
Petrucci was not on a factory bike. The Pramac bikes are a step- or two- behind the factory bikes. That gap is a little closer this year, but it is still a gap. Miller has a very similar bike to the official bikes, but then he is also getting paid directly from Ducati. Jack has a future with Ducati Corse as a MotoGP rider for sure. So does Petrucci.
No one has ever felt that Tito or Karel was anything other than a paying customer for Ducati Corse. That is true today, as it was when Karel and Alvaro shared a garage last year when it was Pull & Bear. Alvaro was on a 2017 spec bike, and Karel on a 2016. Alvaro had 3 top 5's from 19 races, with most of his results outside of the top 10. Again, I dont know how anyone could look at that season and think that he was a future factory rider, especially after 8 years in MotoGP without a win, a new baby, and about to turn 34.
Remember, Ducati uses the Marlboro money to go racing, and further finances it with customer bikes that are a few steps behind. This year, the Avintia bikes are 2018 spec, and could very likely finish top 5-6 with the right rider on the right day. Also remember that the Avintia rides are 'pay to play'. These guys are paying for bikes and support. Ducati does not care who is riding them, so long as the checks dont bounce. (This is certainly the case with Karel, and very likely with Tito)
As an aside, both Karel and Tito are top notch, world class motorbike racers. These guys are fast beyond description, so my comments are not meant as a knock on them, but rather are simply showing the reality of the situation as I understand it.