Honestly I wouldn't even move Helm and Nyquist for Kesler. I'm not saying that because of overall value, but for this particular team it's not worth it IMO.
We actually have forward depth now. Nyquist and Helm play and will continue to play different roles and on different lines. And while Kesler overall is a better player than both of them individually, and he can play Helm's PK minutes and Nyquist's PP minutes, his replacement of them would overall hurt team depth at even strength. You improve one line, but not at the rate of worsening another. And Kesler at even strength isn't as valuable as Helm and Nyquist combined IMO. Not on this particular team. And all of that doesn't take into account that Kesler is likely on the downside of his career while Nyquist and Helm (not to mentioned a potential 1st rder) are on the upswing.
If everyone is healthy, we don't have enough spots on this team for even our good talent. If we can consolidate two good players into one great player, we should do it.
Z, D, Alfie, Helm, Weiss, Franzen, Nyquist, Sheahan, Jurco, Tatar. That's 10 already, 10 players who can all play in the top6 and are showing it. 2 more spots filled by guys like Glendening, Abby (who has played well this year), Miller, Andersson.
If a good trade comes along where we can flip two of our guys for a better player, we wouldn't really be losing even strength depth.
Especially consider a guy like Kesler who would be with the team for at least a few years given his contract. Next year, we may see Pulk, Jarnkrok, make a bid for the team after they've both really turned it up in GR lately. That is some insane depth up and down the lineup even if we have to send two away for Kesler back.
I don't think depth is the issue. For me, it's mostly age and core. Kesler is 29, he's got what, 6 years left tops of the kind of performance expected of a top2 centerman. All the kids we don't want to give up are 22-23 or younger. They've got way more years and we may not even know their ceilings yet. We really need to be looking at life after Z/D and transitioning to a new core. That's my reason for being more hesitant on Kesler.