I guess I'm kinda excited about never being able to find out what happens with this.
Years ago, back in college, my senior thesis revolved around how the value of assets evolved as you became more specific about the market proxy used to measure the risk intrinsically associated with said asset class.
I think the limitations around the CAPM pricing model are very similar to the limitations around win-share based player valuation systems. The win-share based valuation of a player becomes less and less valid as your portfolio of assets (i.e. team) becomes less and less well diversified. And lets' face it. There are almost no well diversified baseball team. Each is engineered to take on certain types of risk. All of which is a fancy way of saying a win is a win is a win until you start to think about the risk associated with amassing a win.
A few years ago I was toying with the idea of converting my thesis into a system that would measure not only the performance, but the volatility of player performance along with the price paid for such performance and volatility. By doing so, you should be able to properly value not only performance but volatility associated with performance (based on other players of a given characteristic). In doing so, you should be able to not only determine the optimal team, down to the player, given any payroll price point and amount of player specific risk you are willing to take on.
I keep hoping I one day hear that the Cubs have built just this.
Next year, we are totally going to win a playoff game.