Ugh, not a fan of this move at all. Just seems clunky and poor usability. I actually know a decent number of non-techies who know about and use the + operator. Seems bizarre to abolish it entirely.
Especially since if you do a search with "+", Google points out that's it's abolished but doesn't change your query for you (i.e. surely it'd also be good for usability to change [hacker +news] into [hacker "news"]?)