I think SJ is solidly in the 15-30 range and D contracts will continue to get bigger as the cap goes up. It's not as bad and as dire as you think and Dom's model is the only one I've seen that continues to shit on SJ since Colliton got fired.
I hate the 'cap is going to up' argument. For a number of reasons:
1) Many teams, including the Blackhawks, have ****ed themselves on the assumption the cap will go up. How about we wait until the cap goes up, and by how much, before building our team around cap space that doesn't exist yet.
2) Any cap increase applies to EVERYBODY, including the teams WITHOUT negative value contracts on their books. Yes, SJ's contract will be somewhat less painful as it represents a smaller percentage of the cap, but it's never going to become a positive use of that cap percentage. All the teams without wildly overpaid players will have MORE of that increased cap space to use than we do.
3) Seth Jones is not traveling at the speed of light. Time passes for him at the same rate it does the rest of us. Which means he's getting older and will provide EVEN LESS VALUE as the cap hypothetically increases. Which means, even as the percentage of the cap he takes up drops, the gap in on-ice value to cap hit will get WIDER.
The benefit of a shrinking cap percentage works for elite players delivering value on their contracts through their prime. You're relying on contracts providing INCREASING surplus value as their percentage of the cap decreases, opening up space to fill in around those players making disproportionate positive impact. A shrinking cap's impact on hiding BAD contracts is pretty minimal, because even if you build out around that bad contract, you still have a player that's giving you less than what he's taking up on the cap, on the ice.