I don’t disagree but Thomas will presumably have a chance at minutes and a role that Dunn was never going to be trusted with
I don't have much concern about negotiations souring Thomas on the organization. Even excluding on-ice usage, there are massive differences between Dunn and Thomas.
Thomas just turned 22. He is a 3 year NHL veteran, but he is also very young and started making an NHL salary quickly. He started making an NHL salary as a 19 year old and we know he hit some of his bonuses over the last 2 years. He topped the $1M earnings mark before turning 20 and he made
at least $3M in his career before his 22nd birthday. He also got the kid gloves treatment as such a young NHLer, living rent-free with an alum and getting NHL perks as a rookie (no busses, per diems, etc).
Dunn spent his first pro year in the AHL making $70k (on top of his $90k signing bonus). This caused his ELC to slide, putting off the time he could earn his 2nd contract for another year. While Thomas got paid his first million as a teenager, Dunn didn't hit that mark until around his 22nd birthday. He hit RFA a couple months before his 24th birthday and had made roughly $2.5M playing pro hockey. He also rode the bus in the AHL in his first pro year and was responsible for finding his own place to live. Simply put, by the time he hit RFA, Dunn had "paid his dues" in a way that Thomas never had to. The development path chosen for him by the Blues limited his earning potential much more than it did for Thomas and that absolutely impacts what a guy expects from his next payday.
On top of that, Dunn didn't have a big question mark season in the year leading up to his negotiation. He took a small step back in terms of production, but still put up great possession numbers and stayed healthy. Thomas had by far the worst season of his career that was impacted by some unknown degree by an injury. He has more incentive (and earnings potential) to look for a 1 year prove it deal than Dunn did.
Thomas is 2 years younger than Dunn was, has earned more money than Dunn had (at comparable ages and off his total ELC) and he has more financial incentive to take a 1 year prove it deal than Dunn had. Negotiations should start in a better place, there is more common ground and the roster shows a much clearer path for Thomas to play himself into a $5M+ role than Dunn had after we signed Krug long-term. I'm not worried about souring the relationship with a just-turned-22 Robert Thomas. We have 4 more years of team control and if he develops into the guy we think he'll be then this negotiation will be a distant memory by the time that bill comes due.