Actually I think putting Bennett in the top and Dupers to the bottom might actually make the bottom 6 better, just not directly. If my eye test of the games isn't failing me over the course of the last couple of seasons then improving the compatibility and strength of the top lines has made the bottom six more effective by basically making it difficult on the other team.
When the team/top 6 is clicking and playing a real puck possession game the opposition defense starts to react to it. They are chasing more, playing more in their own zone, taking more hits, getting "ground down". This results in them being more tired, being slower, making mistakes.
How does this affect the bottom six? Dupuis, for all the things people might not love about him is still a heck of a skater (most games). If put out there against tired defensive pairings he by all logic should be able to recuperate some of his production lost by playing with arguable the worlds greatest player.
Keep in mind, this isn't really meant to be argumentative. I agree there are ways to improve this team. I just don't think the bottom six is the most glaring deficiency, and I think there are ways to make the bottom and top six more effective against more teams in both the regular season and playoffs by simply rotating some personnel.
My line would look something like this:
Kunitz-Sid-Beau (Leaves a 3rd wheel, adds a playmaker to make this line lethal, IMO improves defensively a little and offensively a lot)
Juice-Geno-Neal (Works, not playoff proven yet but I think it has real potential there as well)
Dupuis-Sutter-Kobasew (Still very defensively responsible, Chucky goes to the net, Dupes/Sutter both have the ability to work rushes and cycle)
Glass-Vitale-Adams (While I don't love this line if their play continues it would be very difficult to argue sitting any of them)
Follow up question: if you want to improve the bottom six, who is out? Even with the names I have posted above you still have Jeffrey and D'ags as healthy scratches (we know injuries will probably fix that one though). From a cap perspective, dupuis would be making to much to be in the bottom six, from a bang for your buck perspective it would be Tanner Glass or Brandon Sutter who aren't really living up to their contracts (IMO, that's a whole other topic of discussion), from a pure let's add talent then you would look at all/any member of the 4th line. So who do you swap out?
Like I said, this is all strictly IMO and I don't mean to call you "wrong" on any of this but I just don't see a reason why a seemingly obvious internal solution can't make this a much better team that is more difficult to play against. Your original point of Beau not playing well enough to earn his minutes is what got me going about it and I still strongly disagree with that. None of Sid's wingers have played better than Beau for more than one shift in any game they have played this season. That in concert with the playing style we have already seen from Bennett is more than enough of a reason to see him play with Sid.