would his suing them open the NFL up to discovery and allow access to information that they (the NFL) have been able to keep private to this point?
I'll speculate a bit on this.
The problem is that the architects of the scheme (Goodell and Wells among others) have considerable litigation experience and knew at the time that they had to keep their motivations secret, since Brady might sue for defamation. It is unlikely that they would be quite so incautious as to write an email or text that would be clearly incriminating.
The situation with the NFL employees is thus
opposite to what happened with the Patriots equipment managers. The Patriots employees had no experience in discovery, so they didn't know basic things that people who've been through it know - like not to make jokes in email that could be taken out of context - and the Pats employees also weren't doing anything wrong, so they had no reason to conceal anything. Thus, paradoxically, the NFL employees might fare better in discovery
because of, and not despite, their guilt.
But not always. It's
possible that the NFL architects did let something slip. And it's also possible - and this must be Goodell's nightmare - that one of the ancillary NFL employees has a crisis of conscience and blows the whistle. If such a hypothetical whistleblower saved notes or documents, this could indeed hurt the NFL in litigation.
Legally, the trickiest thing to do for Brady in litigation would be to pierce attorney-client privilege, particularly as to the Exponent communications. Goodell of course likes to claim
both that the investigation was independent
and that all the notes on that investigation are confidential under attorney-client privilege. That's a dubious argument. If the court decides that the NFL waived privilege so that all the Exponent employees can be deposed, there is a decent chance one of the Exponent guys will come clean.
Just in general, I think scientists and engineers might be more willing to tell the truth than lawyers or PR guys, just because of their training. The Exponent report, to its credit, did not seem ever actually to lie - only to leave out critical information. If the Exponent engineers could be deposed, then yes, I think they might well admit to what was going on - that might also be why Goodell is pushing so hard on the attorney-client privilege argument.
That said, I'm sorry to be a glass half empty kind of guy, but it's just
really tough for a public figure to win a defamation case against a well-funded media adversary (treating the NFL as almost a de facto media organization).
Sorry not to be able to give clear answers. It's a complex area and one in which I am sure there are many underlying facts I don't know.