You would put Necas and Aho together? They seem to have terrible chemistry.
Necas and Aho have played well together, just haven't been on the same line that often. As was stated, when they got the extended look, Necas performed at above a point per game pace. While it isn't reality, the chemistry they displayed in 3 on 3 overtime was amazing. Necas is an overtime cheat code.
Right now the Canes are missing a true 2LW. Currently the thought is that one of the youngsters (Unger-Sorum, Nadeau, Blake, even Suzuki with Trikozov being a wild card) may fill that role. I've even see some folks pencil in Robinson or Martinook in that role. It is doubtful that Jarvis will play LW. So the Canes will either promote one of the young guys, trade for a guy, or dance with the players they've got.
I doubt Roslovic will play on the 1st line. Jarvis proved his chemistry with Aho, but many of us think that 1RW is Necas's role for the upcoming season. He wants a bigger role and while he may want to slot in at center, there's nothing in his playing history that suggests he could be the 2C (but stranger things have happened). So 1st lie ice time and PP1 time gives him an opportunity to shine.
Jarvis put up a surprising amount of points on the 3rd line w/Staal and Martinook, so it wouldn't surprise me to see him reprise that role. IMO or top 3 RWs are Necas, Jarvis, and Roslovic in some combo. It's he missing left wing that is currently the issue.