Yup... talent is the real issue and there just isn't enough on the 2nd line. Bednar has his top line safety blanket, which leaves the 2nd line a complete crapshoot of guys who used to do good things. Colton for all of his skills, isn't a 2C either. If he had more talent, he might be a nice option... but it just isn't there.
I don't think it is that the coaches don't like RyJo as much as they know RyJo can't play they way they need him to. He's not a high motor or effort guy... he's not a swift skater. That means he's limited and Bednar doesn't like adjusting his system to adapt to the talent (unless your MacK or Rants). The easiest way to hide that is just not play him as much.
For this regular season, I really don't think it will hurt all that much. Avs have a soft schedule (one of the softest in the league) and the stars can doe enough, especially with the minutes that Bednar will play them, that it can be covered up. Where this will really be exposed is over a series in the playoffs. Especially if the Avs don't jump out to big leads. We're talking 7 games in 12/13 days where if they can't run through normal lines, teams can adjust and attack. You get an OT game or two in there, typically the deeper team recovers better. Say you face a 6/7 game round in the first round, then move into a 2nd round where the test is likely tougher and you're stressing this weakness more and more. There is likely a breaking point to that and that is what the Avs need to avoid. Add to this injuries and the margin for error is just so small.