Assuming no more roster changes, I think some potential shuffling of the Oilers PP personnel could help make a difference in improving the Oilers PP for the upcoming season. I will use some stats (mainly from BehindTheNet - min 40GP + 1.5 PP ATOI/game, but some of my "reasoning" is probably more anecdotal in nature.
(1) Hemsky needs to play more.
He has led the team in PPP/60 for the past two seasons, and either was or was near the team lead in 06/7 (Smyth and Stoll were also close). Last season, Hemsky was t-22nd in PPP, but was 54th in total PP TOI.
(2) Souray and Visnovsky are not well clear of Gilbert and Grebeshkov as PP performers, and should not see as much extra ice, vs. Gilbert and Grebeshkov, on the PP next season as they did this past season.
Both Gilbert (3.91) and Grebeshkov (3.75) outproduced both of Souray (2.95) and Visnovsky (3.07) in terms of PPP/60. This kind of surprised me, I'd love to hear some theories explaining why this happened if Souray and Visnovsky and both vastly superior PP performers to the other two. One might initially theorize that, even if all four players were of equal PP quality in terms of ability to generate their own PPP/60, the two players who played a larger proportion of their time on the 1st PP unit would have superior numbers. This didn't prove to be the case. Is it something to do with Hemsky's style, him being the guy handling the puck for a seeming majority of the time? Just a one season fluke? Is PPP/60 not a reasonably sound way to compare between defencemen on the PP?
(3) The difference in quality between defencemen in terms of power play performance, among the top 4, is not enough to break up pairings.
If EDM is running ES pairings of Gilbert and Souray along with Grebeshkov and Visnovsky, the increase in PP performance may not be worth the "problems" that come with mixing and matching the pairs. It may well help the ES performance to keep the pairings the same on the PP, if it means you can play your top 4 an extra shift or two perr game instead of some filler variation spotting in Smid and Staois until players are back in their pairing.
That said, this may not be a big problem to begin with, and if it isn't then I don't think it's a bad idea to break up the pairings if you feel it gives you a much better power play. I'm straddling the fence here, I know, and not committing either way, but it's hard to know how the Oilers will approach things without seeing what the new coaches do for ES pairings, the PP pairings, if they are willing to go with a 4th F, etc.
(4) Robert Nilsson may have the potential to be a much better PP performer than he seems to be given credit for.
Last year was only one season, but Nilsson was 2nd in PPP/60 among Oilers who played in 5 or more games (I set this arbitrary 5 GP min to exclude Schremp, who led the Oilers in PPP/60 - 5.31 - in an extremely small sample size of 4 games and 11:18 PP TOI). I don't recall much for 1st unit PP time either. I'm not sure how well he would work with Hemsky on the PP, but I think it's at least worth a look for a couple of preseason games in training camp. His previous year wasn't nearly as strong, and it may be that the bounces were simply going Nilsson's way last year (can I check that with Vic's site? Is there some other way to check that?), but he's also probably around the age where some NHL players see their PP production start to rise. Maybe there's potential for him to be a strong PP performer at the NHL level; it would make sense given his draft day scouting report.
(5) It's not impossible the Oilers see both units increase in production if Souray is separated from Hemsky.
Actually, that's a bit of an overstatement/misrepresentation, since if Hemsky is playing as much as I'd like he will be on both units, coming off the ice after 75-90 seconds of PP time when available to start the PP, he would still be playing some with Souray. I guess what I really mean is that the PP tends to become static around the perimeter of the box when Hemsky and Souray are playing together. Or maybe that's just how I remember it, but my impression of that PP unit is that it does not look enough to the other three options.
When playing together, I think the Oilers PP unit would produce better if Souray's slapshot were coming from 5 feet closer after the Oilers look to attack a bit more frequently down low.
When playing apart, I don't think the Souray unit (potentially) loses as much, if Souray's point shot is the focal point, as the Hemsky unit gains by using, say, Grebeshkov and Visnovsky and trying to get players creating motion in the offensive zone.
(6) O'Sullivan and Cogliano may be decent candidates for cut minutes on the PP.
Neither player has a great track record in terms of PP production. This isn't to say that they are awful, can't improve, or that they wouldn't be respectable fill-ins if someone I might currently play ahead of them struggles or is injured. But in some ways cutting their PP minutes is just as much a function of these players being PK options, in my mind.
(7) I like Penner as a PP option, and I like him on the same unit as Souray, but I'd be curious just how much his production would drop if he played on the second unit with the half Hemsky, half O'Sullivan/Cogliano in place of his first PP production. My guess is he is less dependent on playing with Hemsky, if that proves correct I think it might well make sense to move him to the 2nd unit with Souray, which could theoretically improve both PP lines.
So, to sum, here are two PP units I wouldn't mind seeing get a couple of exhibition games, not set in stone, but IMO worth a look:
(1) Nilsson Hemsky Horcoff Grebeshkov Visnovsky, changing when the puck is iced after 50-60 seconds, except for Hemsky.
(2) Penner Gagner Hemsky/Cogliano/O'Sullivan Souray Gilbert, where Cogliano/O'Sullivan replace Hemsky, when the puck is iced, around the 1:20-1:30 mark.