Pittsburgh rolling a top line of Kunitz - Crosby - Dupuis is just fine. They probably win that series with Dupuis. And it doesn't really matter what caliber of player Dupuis is, he works with Crosby and that line so on Pittsburgh he's a first line winger.
Two examples to prove my point.
Craig Conroy was not a 1C. On Calgary, with his chemistry with Iginla, he was a 1C
Matt Lombardi was definitely not a 1C. On Calgary, the line of Cammaleri - Lombardi - Iginla was dynamite. Then they traded Lombardi to bring in Olli Jokinen, a true "1C" and that line fell apart. If the line works, it doesn't matter what the skill level of the individual components are rated as. This reference might be a little harder to remember, but that line was rolling until they lost Lombardi and got Jokinen.
If Dupuis is playing, Pittsburgh is icing a lineup of
Kunitz - Crosby - Dupuis
Jokinen - Malkin - Neal
Bennett - Sutter - Stempniak
Gibbons/Vitale - Goc - Adams/Glass
In terms of skill and balance, just 1 player makes this a MUCH better lineup. Pittsburgh probably doesn't lose with this lineup to New York. Boston/Montreal different story, it is tough to say.
Bennett has just shown he's not a top 6 guy, at least not yet he isn't. No I don't think the Penguins need a massive overhaul. Trading Malkin would be a terrible idea, unless you're getting like a Weber back. There is almost no version of a Malkin trade where Pittsburgh wins the deal.
Someone speculated signing Kulemin as a FA. Played and has had chemistry with Malkin in the past, should be cheap, brings another Russian on the team to make Geno more comfortable. I don't think it is a terrible idea except I'd rather see Jussi on Malkin's line instead.
I'd prefer them get rid of Letang and keep Niskanen, but that might not be possible. Time for Orpik to go. Fluery wasn't the problem. Does firing Bylsma help, if they can bring in Trotz? Maybe, really tough to say. Minor tweaks, but any major moves IMO makes the team worse not better.