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.
This is a tough question to answer. The fact is that your typical fantasy league is going to value stats that have little predictive or descriptive value such as RBI. I think that the BE score would be a good metric for how valuable a player has been in one of these kind of fantasy leagues in the past. However, if you're wanting the BE score to be predictive of future value to a fantasy team, what you're really trying to project is future performance in general. If you want to get into that, the inputs that you have aren't sufficiently predictive and you're going to have to lean on more advanced metrics. As far as I can tell, BE weights all of the 7 stats exactly equally. The truth is that RBI is a terrible stat and VORP is an okay stat, for instance.
There are some really smart people out there working on projection systems that you could look into. Dan Szymborski does ZiPS, Tom Tango does Marcel and then you probably know about Bill James who has a projection system by the same name. There are others, but these are probably the most popular.
I'd love to offer my assistance; baseball nerdery plus development nerdery would essentially be my dream job, but I would be way too swamped until June or so to be able to contribute. I don't know how SABR savvy you are, but my contact is in my profile and you're welcome to bounce questions off of me. There are also tons of resources out there I can direct you to.
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.
Unfortunately, I have no answer for that. I'm not a fantasy anything player, so I really don't know what would be useful. I can get ahold of my friend though, a (sports) journalism major who plays a few leagues at a time, and see what he'd like :)
If you take a look at the data table, you'll see that in the BE Scorecard & statistic value columns they are either colored green or red. I'm doing a least-squares linear regression on the player's BE Score here and showing red if the player's BE Score is trending down over the last 30 days or green if the player's BE Score is trending up over the last 30 days.
I'm currently building a voice-to-text transcriber using the Web Speech API.