I’ve been trying to figure this out as well, so I changed the bloom settings in the Post Processing Volume to match the ones in 4.14. If you do r.TonemapperFilm = 0 in the console, it looks at least close to how it used to.
Really hoping they reconsider removing that r.TonemapperFilm = 0 option in the future, it looks so much better with the old tonemapping for my project, at least. I understand the importance of realism in many projects, and appreciate that they’re trying to make the defaults that way, but that doesn’t mean other methods need to be completely tossed out (although there’s probably a way to remake it from scratch if someone has sufficient understanding). I guess if they do get rid of it, hopefully someone finds a way to fake it with the new settings or something and posts how they did it publicly.