Adding Tkachuk only makes sense if we can get him to a team-friendly deal like Gaudreau's contract, and are able to trade for him for his total value -- and that includes the fact that he has only one year left on his deal. There's just no way in hell I trade Kyrou for Tkachuk. Calgary WISHES they could make that trade today. Why would I offer that for a player that is more of a luxury, is going to get PAID, and when we have the ability to bring him in for zero assets other than cap next year?
For those of you saying one of them has to go, even if that were true, that doesn't mean you trade Kyrou for Tkachuk. You could just as easily trade a package of Tarasenko+Kostin+Scandella+2nd (which is quite a haul for a player that is going to walk on them), and then turn around and trade Kyrou for something of actual need that represents his value (a #1LHD to play with Faulk/Parayko).
The only way I can see Kyrou being traded is if we get Tkachuk+Hanifin for him and some loose change, and I don't think the Blues need to do that. There are plenty of LHD on the market we could be targeting that wouldn't cost Kyrou: Sanheim, Provorov, Chychrun, Hanifin (with no Tkachuk), Dobson, and plenty others.
And now for some fun,
My offers:
Tkachuk for Tarasenko, Scandella, Kostin, '24 2nd
Hanifin for Barbashev, Mikkola, '23 1st, Matt Kessel
Scandella can be traded to someone else, but I think Scandella is the cost of value for Tkachuk. +/- on both sides to make things work, the Blues come in under cap with Krug or Leddy on the way out next year -- making room for Kyrou's raise. O'Reilly can then re-sign comfortably.
Hanifin, imo is the real target, and is both the best fit of the available LHD skill-wise, and especially cap-wise.