Even without a home plate "exception", I still don't think it would be a terrible call. The baseline in that situation isn't the literal baseline, the runner's baseline is established as the path he's on as the tag attempt is made - Ichiro was coming in wide to begin with when Weiters tried to make the tag, he didn't go that far from the path he was already taking. Might have outside of 3 feet, but not by a lot. It looks worse because he also ran past the plate.
seamar is right though - it's a moot point if Wieters doesn't give Ichiro the opening by going after him on the 2nd attempt.