Very interesting, things could get really bad for EA here especially seeing as the people making the complaints have generally not taken the "clarification of the ending" offer as an actual solution and the fires have continued.
The BBB is not a goverment agency but it does have a lot of power, largely because of the organized pressure it can put on companies via their distributers, the information they release, and other things they can do. They have literally decimated businesses, including some pretty big ones in the past. Truthfully I am surprised they agreed with this since digital products/games are a bit outside of what they generally handle.
At the very least the expert opinion of the BBB is going to probably influance the FTC which CAN take action on these grounds assuming the guys bringing the complaints decide to referance this (and they would be stupid not to) the BBB being experts who have been around for a verrrry long time, and exist for exactly this kind of thing. This means EA might very well be getting slammed by some huge penelties, even if it takes a year or two for this to all be sorted out (the wheels of justice move slowly). That "lulzeworthy" legal complaint just grew a nasty pair of fangs, since the BBB does know this area of law and how it's supposed to work (it's their thing).
I'll also say that it remains to be seen what action the BBB is going to take, it can be slow, but I wouldn't be shocked if we wind up seeing a lot of retailers start pulling EA/Bioware products from their shelves, and perhaps even a drop in stock price if the BBB starts calling EA/Bioware a bunch of liars in their distributed literature (where they review companies and such).
Don't expect the sky to fall tomorrow, but the BBB tends to carry more weight for more people than say your typical complaint about something being "racially insensitive" or potentially "bigoted towards homosexuals" and other divisive issues. If the BBB decides to actually start blasting companies like Gamestop, Wal*Mart, Target, or various digital distributors for being crooks by helping push the products of crooks... rather than fight the trend and wind up losing in a case like this when other people notice the press, they are going to comply. It won't be played out entirely in public, but don't be surprised that if EA doesn't satisfy the ME3 "Line" at least enough to end the rage, if say some Christmas you have a hard time finding EA's newest releases on the shelves of major retailers.
The big issue here of course is what the BBB can do digitally. Generally speaking there isn't much they are going to do to EA's own platform (Origin), but it does mean that if EA decides it wants to release more through other platforms again, they might find companies like STEAM hardly waiting for them with open arms given that this is yet more baggage they bring with them.
Time will tell, but this is potentially a big deal, the BBB is one of the best allies you can have in something like this.