Normally moving a 100 point 23 year for two players north of 30 isn't a recipe for success. Especially ones that has as many questions as Letang and Kessel.
Letang is a beast when healthy and on his game. But he's also a guy that has had major health scares, and as recently as last season had Pittsburgh fans ready to run him out of town for his play (and that was a "healthy" season).
And considering how temperamental Kessel is, I'm not sure a fish bowl like Edmonton is the best spot for him. I mean there's a reason Pittsburgh is ready to move on, even after he put up a ppg.
If this was a trade built around the 8th, or even Nurse/Klefbom/RNH, then sure; but Draisaitl's not a name that should be anywhere near this conversation.