Speaking Moistly
What a terrible image.
I was kind of hoping they'd put better playmakers/play creators with Sheahan to start out. Hagelin and Horny obviously bring value to this team, but more as complimentary wingers on a line.
Kessel, Guentzel or even Sheary would be better options for Sheahan, IMO.
Even without Sheahan just some different combinations. HH lacks creativity, GCS keeps having defensive problems and Sheary is on his off wing, Malkin and Kessel have been whatever you'd describe that as. Sheary, Guentzel and Kessel all on separate lines; Rust, Hagelin and Hornqvist all on separate lines.
I'd go
Guentzel-Crosby-Hornqvist because Hornqvist belongs there and should work well with GC if they're left alone
Hagelin-Sheahan-Kessel because I want Kessel away from Malkin and forced to drive his own line. HK is a wing duo I like.
Sheary-Malkin-Rust is a bit more of the leftover line but I like Rust with Malkin, Sheary has had some good moments with Rust, they could be a complementary wing pair and I'm curious about Sheary with Malkin. If it fails Rust can move to LW when Sprong comes up and that could theoretically be a nice wing pair.
Leave that for 5-10 games and then reassess but the fundamental part is having a creative winger on each line.