I think there is little argument to be made that the trade would not favor us. Atleast the way Patty has played this season. Shattenkirk has 27 points in 44 games. Patty has 32 in 50 games. One is a D-man and the other is a forward.
Losing Patty would hurt, but basically slot Couture back as the 2nd line C once Patty is gone. Try to acquire a decent 3rd line C by the TDL. That would be a lot easier (and most likely cheaper) than acquiring a top-6 Forward.
All this being said, there is no reason St. Louis should consider trading Shattenkirk for Patty unless there is a significant + coming from our side. As pointed above, both are scoring at a similar pace but Shattenkirk is younger, cheaper and also a D-man. Plus Marleau has been slumping badly off-late. St. Louis requires a boost in scoring and I am not quire sure Marleau in his current form quite fits the bill.
Well, to be fair, Marleau's current slump in production may be as much about the role he's being asked to play right now and the linemates he has to work with. He's been a LW for years now, rather than a C, so he's had to adjust to that on the fly. Plus, the wingers he's had on his line aren't exactly top flight offensive goal scorers. He produced when he was with Couture before he got injured, and he produced at a much higher rate when he was on Hertl's wing as well. Also, it seems like he's being used in a defensive-oriented role rather than an offensively oriented one, which also cuts his numbers. And hell, we all know how streaky he can be, we've seen it for how many years? For all we know, in 2 weeks he'll have a 10 game stretch where he gets 8 goals and 17 points and we'll completely forget about the current slump.
If St. Louis puts him on their first or second line as a LW, and gives him a quality playmaking center to work with, I think his production would increase dramatically. Especially if he's told that his primary focus is to be on offense, rather than his current defensively oriented role. St. Louis could probably get away with that, since their D corps is pretty damn good, even without Shattenkirk, so they don't NEED him to concentrate on D as much as the Sharks do.
That said, I am in complete agreement that there's absolutely no way St. Louis makes that trade on a 1 for 1 basis. We'd have to sweeten the pot somehow, with at least a pretty decent young player. I don't know if we'd have to include Goldobin or Meier along with Patty, but there'd have to be SOME obviously valuable piece. Labanc or Shadow might fit the bill to some extent, given how much they're currently tearing it up in juniors. Does Marleau + one of Labanc/Shadow/Chartier + 3rd round pick get us close? I think probably, but I could be out way beyond left field, too.
There are obviously a couple issues there. Fear the Fin actually discussed the possibility of a Marleau for Shattenkirk swap a little while back. They said it seemed like a good fit for both sides, except that St. Louis would obviously want another quality piece given the age difference. On the other hand, Doug Wilson has fan sentiment to keep in mind, and given Marleau's stature among fans, there could be a very big public backlash for trading such a popular elder statesman of the team unless he is perceived as definitively winning the trade. As a result, DW would be very reluctant to add too much to the trade on top of Marleau. Also, we have no idea if Marleau would even agree to waive to go to the Blues. They're really not that much better a destination for him if his goal is winning a cup than the situation he's got now on the Sharks.
Still, getting Shattenkirk just makes way too much sense to completely ignore the possibility. Getting him fixes that D depth problem pretty much completely, as well as giving us an immediate boost to our defensive play and the potency of the 2nd PP unit, which I'd assume he'd QB, with Burns on the #1.
Now, if DW wants to REALLY catapult us into the ranks of serious Cup contenders, he'll find a way to trade for both Kadri and Shattenkirk, without losing any roster players other than Marleau.
It would be like dream! Of course, the odds on that happening are, to put it mildly, "slim".
Still, a guy can dream, right?