Why does Carolina want Allen?

Maybe they don’t want him, but the Blues should be able to get this return for a .927 goalie who’s .913 for his career

Why not move Bozak instead? More cap off, more interest likely, less harm to your team.

Keep in mind that goalies rarely get what they should. Allen's down year two years ago will definitely come into question, and a team without a viable starter would be raising eyebrows. That's why BUF is the only team I could see being moderately interested in Allen, yet still that package would probably include Hutton.

Bozak would be ideal, but he’s got an NTC and probably gets a worse return than Allen.

However,
It's only a 10 team NTC. The thing is that I think Bozak would have far more interest than Allen - and when it's a matter of cap, the return probably does not matter. Having a 3rd vs a 4th is meaningless when talking about bringing back your captain and team-best defenseman.

Maybe you’re right, I just think Allen is probably the more movable player. I’d imagine Vancouver would be interested (depending on Markström of course) Carolina maybe, Washington, Buffalo, Ottawa, Edmonton. So much is gonna happen between now and whenever this goes down so who knows.

Vancouver's dependance on Markstrom is rarely thought of in this city because of how very likely it is that we bring him back. Even if we don't, I would see other goalies being targeted first in free agency. I know the FA market on goal is slim with most goalies reupping where they are. EDM and BUF are maybes.
Allen shouldn't be the primary starter on any team, so a jobshare is ideal.
I guess my overall point is that you will probably have to take whatever deal comes your way, given that Pietro is far more important than the position of the pick.

What about trading Allen to Calgary? Rittich isn’t a starting caliber goalie in my opinion, 2.97 GAA and .907 sv % isn’t good enough between the pipes for a team to make a deep postseason run and Talbot is in the final year of his deal and will be 33 at the start of next season. The Blues could look to target Zavgorodny or Phillips along with a 2nd or a 1st if they sweeten the pot a little

I like it and it seems feasible given Calgary is likely in for quite a bit of change this summer. Maybe toss in Blais to help the return.

Blais is exactly who I would throw in to sweeten the pot

Definitely could work depending on the return