I offered a conditional pick. You could have countered for something like a 2nd or Sprong since the Stars need goal scoring. You also could have done a counter proposal of something like Hagelin+Vanecek for Khudobin with retained salary or something.
If Raffl and Holtby were traded separately, you might get a 4th round pick for Raffl and a 3rd round pick for Holtby. Whether combined in a trade or separate, the Stars would gain assets because they signed both to 1 year contracts.
I made the counter but you're just not satisfied with the explanation. Anything outside of picks or futures like middling prospects makes little sense to Dallas. There's no further debate necessary or counters to take on a salary dump or backup goalie when discussing those two players you specified.
Something around Hagelin and Khudobin isn't impossible to see happening but it also has nothing to do with your original post about Holtby and Raffl. That's something I could see Nill doing (he's done Gonchar for Moen before just to shuffle the deck and move out an overpaid vet at one position for a different one). Holtby or Raffl would be entirely separate deals, and your example of a 3rd and 4th for those 2 guys is better for Dallas than adding payroll and a backup goalie.
You either wanted an honest evaluation from Dallas' perspective or not. The reality is Hagelin and Vanecek likely have less value to Dallas than picks. Your new discussion about Khduobin and Hagelin isn't out of Nill's wheelhouse, but personally, I wouldn't retain money. That's doesn't mean in a fair world Dallas should I'm only saying Dallas already had an easy solution with Khudobin. Say they retain $1 million to make that deal happen ... fine, you're still stuck with a forward that doesn't fit with the team. Just buy Khudobin out and be done with it. He'll be owed less than $1 million next season and $1.25 against the cap the following season.
From a Dallas perspective, Hagelin or Vanecek don't make enough season to try and come up with creative counters where 1 or both of those guys end up in Dallas.