I think that it was the whole point of replacing the My Topics with Bookmarks: stop tons of emails going and stop E looking like spammers in the eyes of mail providers...
That's odd as I only got emails from the threads I'd set to 'Notify'. By default every thread I posted in was then set to 'notify' but it was a simple matter to click on the tab and turn it off once you got used to it.
But I think the new bookmarks system is as good, if not better since all the bookmarked threads now show on one page (at least my 40 do) which they did not before so I'm very happy with that alteration. I do still get emails from every thread I post in unless I switch them off though, so the "E possibly seen as spammy" aspect is still there.
It just takes a few minutes in your profile to alter the settings... I suppose many users don't know they can do that?