I think the purpose of the ending was to take out Moriatry's organization out of the show, at least for some period of time. Remember Dad said he was pulling it out of New York.
I thought here sister's transformation happened a little to quick and seemed too convenient. I'm usually quite tolerant of this kind of thing, usually.
I find that even average Elementary episodes are better than most other dramas on TV.
When I first saw this on the preview after last weeks episode, I was close to falling off my couch. It's not often I laugh out loud. Homes delivery of the line was delicious, conveying how wily he thought the whole superhero genre is. Wonderful. That line alone is worth a renewal.