The "trailing bang" (eg imdb!) is a syntax engraved in my (and I imagine may other people's) muscle memory after a long time of extensive use and it is very hard to change. Even though it is an annoyance that ddg no longer has the behavior I expect the biggest problem it makes it really easy for phishing sites to com up very high on the search results. For example the query "imdb! constantine" yields this imdb1.ir/title/tt3489184/ as the second result and the only one referring to the tv-series.
I know there have been enough flame wars over this and not to sound like a zealot but I don't think breaking trailing bang queries is a good move.