Figured I would duplicate my two main comments here for everyone on CD to enjoy/discuss
For both the app and website: I'd love to see a direct connection (in the form of "comments" on the side?) between the rules and the FRC Q&A. Both the rules and any Q&A responses that pertain to those rules are really needed to fully understand design constraints on the robots.
The ability to "subscribe" to changes to specific sections or subsections, so I could receive an e-mail containing updates I'm interested in. Often teams are broken up into subteams, where each subteam may be interested in a different portion of the robot rules. For example, the electrical team is the only one really interested in the Power distribution subsection, while the PR/awards team will be the only ones really interested in the Awards section.
And of course, I mentioned the app's limitation of viewing one rule at a time. I ended up ditching the app and just loading the PDFs onto my iPhone... much easier to scroll through and find the rules I wanted to look at.