I have peppered in some comments throughout this thread, but I've got loads more. Give them a read and dont hesitate to contact me if you'd like to share ideas sometime.
"Another issue is that selection of stat categories for the "BE scorecard" does not match up with most fantasy baseball 5x5 leagues since it is missing AVG."
Tyrone, it seems like your site's main marketability strategy is to allow fantasy owners big and small to customize their own comparisons and data visualization based on the stats they want to see. So with the above concern raised in mind, what if you allowed users to input their own 5x5 categories for their league and boiled that down into one number?
For example if someone was playing in a league that counted just Hits, Runs, Stolen Bases, Home Runs and OPS, and they wanted to know how Alexi Ramirez was doing in this format, they could just input these five stats and create a "Custom BE Rating".
This way, the hardcore data crunching aspect is still there, but the user will still be able to get a full amount of value from the site because it offers them the ability to tailor the data to their own league.
Pay structure should include a free 10 day trial. That way users will be able to see what kind of advanced stats and analysis that is provided. Through the free trial method, users will get a small sample of the site and develop a dependency of sorts on the site's analysis and find themselves needing it for the rest of the season!
There appears to be a lack of advertising on the site as well. Seeing that you work for Google, I'm assuming its not because AdSense wouldn't accept the request for ads, but a strategic move on your part. Nice job, it looks very clean and easy to trust. Having no ads at this phase in the site's development is a smart move, and as the site gets more web traffic it might be a smart idea to reevaluate.
@sparkygoblue Is anybody using this API? If so, have you ever used YQL? Since it integrates so many other languages like JSON, do you know how different it is from SQL?
Tyrone, first of all I love the data visualization efforts. As a personal baseball stat nerd myself, I always appreciate a site with in depth stats.
As for a football version, since the format is week to week you should heavily consider incorporating weekly matchups for players (ex. Arian Foster vs. Indanapolis Colts Defense, at home). There are a few good resources that I could direct you to for projecting matchups, but if you made your own incorporating split stats you could honestly provide a great resource to fantasy owners and, with the right marketing, capture a good portion the fantasy football market.
Positions are much more important for fantasy football than they are in baseball, so the tabbing system you have right now to distinguish pitchers and hitters is good, but expanding that concept to QB, RB, WR, WR/R, K, DEF would provide a good resource for all fantasy owners.
If you have any questions, email me. I'd love to help you out with this, and I could go on and on about where you could take this idea. The market for this type of site is just getting off the ground! My contact information is in my profile.