Webber is at least as good as the likes of Button, Massa et al. I can't see Ricciardo doing any better.
What do you base that on, he has had the second fastest car this year, fails to qualify well compared to Vettel, can't get the car off the grid with 4 years of practice. Though in fairness Vettel has also had issues off the grid but I think he has improved over time. Though Hamilton has quite clearly out started the Red Bulls in terms off getting away, but being behind the Red Bulls the two red bulls have done very well to squish Hamilton into oblivion for three races
But I basically see no reason the second fastest car on the grid shouldn't be comfortably in second place in the title race. Okay, he certainly has had bad luck, but Vettel has also had failures, Vettel has also had Kers failures and most importantly RBR without Kers is still way faster than every other car so that isn't much of an excuse.
Even in a perfect race he's in dirtier air than Vettel(assuming he's following Vettel) which does make the car less good. But the amount of times he makes contacts, generally can't get the same speed out of the car in the same conditions. Some of the point loss is down to failures, some luck, much of the disparity is due to him being a worse driver.
I do think to some degree drivers who become no.2 drivers tend to take on a "can't be arsed" style of driving. Where Massa driving for a contract has been significantly more impressive than Webber. But personally I find drivers who try less hard because they are no.2 drivers are, *****.
Would anyone here turn their nose up if given the no.2 driver role at Red Bull, or Marussia for that matter, would you try less hard or race less hard if the team focused on the better driver, I wouldn't. I understand some drivers give up, but for me that is part of what makes a driver less good, not an excuse for being less good if you see what I mean.
Will be interesting to see what Ricciardo can do, I would expect him to take time to get to grips with how the team works, their methods, his engineers, setup, even the steering wheel(unless being a feeder team they make a huge effort to keep some of those things as similar as possible?).