I think that some people here are overvaluing the 10th overall pick when they want to throw Pospisil in.
Here are the 10th overall picks from 2020-2000:
FP(5%):
Rantanen(2015)
P1/L1(20%):
Bouchard(2018), Tippett(2017), Nichushkin(2013), Brodin(2011)
P2/L2(10%):
Perfetti(2020), Frolik(2006)
P3/L3-4(35%):
Podkolzin(2019), Jost(2016), Ritchie(2014), Paajarvi(2009), Hodgson(2008), Kostitsyn(2003), Nystrom(2002)
RL(30%):
Koekkoek(2012), Mcllrath(2010), Ellerby(2007), Bourdon(2005),Valabik(2004), Backburn(2001)
Which means that the Flames would have a 65% chance to draft a player that's significantly worse than either Markstrom or Pospisil. You can even argue that I have Frolik, Brodin, and Tippett too high. That said there's a 1/4 chance to get a core player.
I would obviously be happy with the 10th overall pick as the return in a Markstrom trade, but the expectations from that pick here are extremely high. Nystrom was 10th, Baertschi was 13th, so was Coronato. IMO Pospisil is better than either of the 3 were/are.