The way I look at it, is take Brunner and Briere out of the deal. They're inconsequential pieces....sure Brunner has some upside, but he's a couple bad games away from being buried and then heading back to Switzerland in the summer. Briere is old and his days of being fantasy-worthy are over or at least very limited.
So the deal then becomes Hall, Ryan, and Richards for St. Louis......yuck. I love MSL he's one of my favorite players, but there is no way I would ever make that trade. Hall has had some injury issues, but he was on a 70-ish point pace last season. MSL won't outscore him by that much, and Hall is like 16 years younger or something. Ryan will be fine, he's had a slow start but that just means he'll turn his season around later on and be a beast for you down the stretch. Richards is a bit "meh" but at least there's some upside with him for 55-60 points.
So I would not make this trade. If you're looking to win this year, I think the players you currently own give you a better chance at that.
20 Team Dynasty (points per) - G (25, 50 for defense) A (25) PIM (3) +/- (5) PPG (15) SHG (25) OTG (15) GWG (25) HTr (50) GP (2) HIT (1) BLK (1) Use actual NHL salary
F: Malkin, Tavares, E. Kane, Parenteau, Havlat, Tarasenko, Galchenyuk, Brunner, Boyes, Kruger, Helm, M. Martin, Bergenheim, Carcillo, Stajan
D: Green, Ehrhoff, Ekman-Larsson, Coburn, Daley, Postma
G: Fleury, Mason, Montoya
Farm: Grigorenko, Grimaldi, Kucherov, D. Shore, Hartikainen, Stransky, Kerdiles, Joensuu, Pageau, Murphy, Ceci, Klefbom, Thrower, Donovan, Ekholm, Lehner, Dansk, Poulin, Nilsson, Andersen