As far as the draft pick goes, it's certainly possible, and perhaps even likely, that a deal for another pick (moving up or moving back) could hinge on a couple of spots, but dose a deal for a top 6 quality player hinge on that?
Generally speaking, teams aren't moving top 6 players because there's a very specific prospect they are targeting at the end of the 1st round...they're doing it because he's a pending UFA, or too expensive, or they're rebuilding/retooling, etc., and they're looking for reasonable value for the asset they are moving. In that sense, they're probably not going to be splitting hairs over a couple of spots for a late first, which inherently has speculative value regardless of who you draft there, if they like the rest of the package otherwise.
If the Blues keep the pick, it's impossible to know how a couple of spots might affect their chances of moving up, moving back, or who they'll have a chance to draft...if we ever know some of that at all. Everything will be fluid right up until the end of the 1st round, and most of what is affected will be happening behind the scenes. Personally, I would have gotten no sense of enjoyment if that pick had ended up 27th instead of 29-31st...probably not even if it had ended up 23rd. Any benefit is completely speculative, which makes it hard for me to invest emotionally in the outcome.
Besides, that pick is the proverbial icing on a ****-filled cake of a season. I doubt it's going to taste sweet until it actually turns into something that makes me think this travesty of a season was worth enduring so the pick could be obtained.