We're clearly watching different teams. I'm watching the one where Del Zotto was the #4 (and often higher) D on this team for the last two years. Every single stat corroborates what my two eyes are telling me. I will not agree to disagree, because your position is based on absolutely nothing. Del Zotto has had more points, more PP production, more ES minutes, more PP minutes, more PK minutes and tougher match ups. There is literally nothing at all to support your idea that Stralman is anything more than a #5/6 defenseman.
Who out of the following will be sitting or demoted to bottom 6 after you acquire said LW? Stepan? Callahan? Nash? Richards? Brassard? Hagelin? Kreider? MZA? That's 8 guys who will likely, at least at some points during the season, get top 6 minutes. That's not even taking guys like Hrivik or Kristo into account.
Hags Stepan Nash
Richards Brassard Callahan
Kreider Boyle MZA
Pouliot Moore Dorsett
Powe Miller Pyatt
Asham Mashinter Kristo
Those are all guys who have NHL ability (with the possible exception of Mashinter). Leaving Mash out, that gives us 5 extra bodies at forward. Keep a spare or two, and you still have three to four extra forwards. The ONLY place where it makes sense to subtract from the defense to add to the forward pool is in your imagination, with your irrational take on MDZ as a bottom pairing D.
Incidentally, my bet is that Kristo or MZA solidify a spot on the 2nd line RW, giving us a top 6 of:
Nash Stepan Callahan
Hagelin Richards MZA/Kristo
Kreider Brassard Kristo/MZA
During the reg. season 2012-13 Del Zotto was definitely ahead of Strålman on the depth chart. MDZ was the #4 with healthy Staal, and #3 after his injury. No debate from me. Strålman did however pass Del Zotto on the depth chart at ES in the playoffs, where he in the end was on the top pairing with McDonagh.
Regarding matchups, most stats say that Strålman got slightly harder matchups than Del Zotto. The only metric that puts MDZ above Anton in that regard is Corsi Rel. QoC, but that is more useful when comparing players from different teams. Straight Corsi QoC is more representative when comparing players from the same team as they have faced the same teams the same number of times.
For example: Playing against Clarke MacArthur (16.2 Corsi Rel., -3.93 Corsi On) will give a higher Corsi Rel. QoC than facing Patrik Elias (10.5 Corsi Rel., 18.57 Corsi On), but facing Elias (and his superior possession numbers) will give a higher Corsi QoC.
I genuinely believe that Strålman has the capacity of being more than a #5/#6 because of how he performed last season. As I have shown time and time again; Strålman blew Del Zotto out of the water in every available metric other than points last year being used in very similar situations.
Regarding top-6/bottom-6: that's an entirely outdated concept to me. What you need is: 6 forwards that can play on the PP, 6 forwards that can PK, and a roster that fits under the salary cap. Other than that you just want your forwards to be able to outplay (mainly outpossess) and outscore the opposition. With the salary cap, you will have to have a few specialists that are only useful in specific situations and you won't be able to roll 4 good lines. But three guys on the 4th line is entirely sufficient, and if you have the horses to roll three good lines at ES you should definitely do it. For example I'm entirely convinced that Pouliot and Zuccarello are going to be a lot more valuable than Dorsett, and they are both paid less.
You did however post a top-9 at the end of your post, so I don't want to paint you someone who prays at the altar of the bottom-6 god.
This is a quote from Dave Tippett about defensemen, but it applies to forwards as well (and Anton Strålman for that matter):
Dave Tippett said:
"We had a player that was supposed to be a great, shut-down defenseman. He was supposedly the be-all, end-all of defensemen. But when you did a 10-game analysis of him, you found out he was defending all the time because he can’t move the puck.
"Then we had another guy, who supposedly couldn’t defend a lick. Well, he was defending only 20 percent of the time because he’s making good plays out of our end. He may not be the strongest defender, but he’s only doing it 20 percent of the time. So the equation works out better the other way. I ended up trading the other defenseman."