.... how is ME3's ending EA's fault? Didn't Bioware make the game?
EA is the publisher, and dictates terms to Bioware. If you were to be the publisher, and saw the opportunity to pump money out of a fan favorite series, wouldn't you take it?
In order to pump the most money out of a franchise you need it to run into the ground (see: FIFA or NFL yearly games). In order to do this you can't have a satisfactory ending that closes all plot threads, or your fans won't have anything to come back for. EA needs an open ending for future games.
Bioware promised us a trilogy nearly a decade ago. Trilogy means three games, that wrap up all plot arcs. In case you missed it, trilogy doesn't equate to a cash cow.
EA, holding the pocket book, told Bioware to leave the ending open for an easy sequel. Bioware said they promised closure, EA said do it or we cut funding. None of this is illogical or backhanded, unless you're a consumer that is. Bioware made a promise, EA redacted it with money, consumers get boned.
EA therefore screwed up ME, like they do with all of their franchises. Enough said.