I agree with a lot of what you're saying but I have some issue with the bolded. You're making it seem like he's been dealt a bad hand and he's out there making the best of it. But that's not really the case. He's been dealt a pretty good hand (top six, offensive zone starts, powerplay time) and consistently done nothing with it. He's never had to earn opportunity in the same way that Joe Veleno (for instance) has. So of course he's been a good teammate/had a good attitude.
Look at how everyone talks about him. When he sucks the entire conversation revolves around "how can we change the entire lineup of the team to get Zadina going". It's never "Zadina needs to work his way up from the fourth line through his play". The same thing used to happen with Brendan Smith. Without a hint of irony his slappies all thought he should play with Lidstrom/Kronwall to "get him going" without ever considering whether it was good for the team to have a loser on their top pairing.