I'm not optimistic about this change, but I'm okay with being along for the ride.
Generally, I hate using tags for sorting. They slow down my reading, cause confusion, and are generally inaccurate. The only board I have ever seen with a tag function that actually worked was one where the tags were reader-generated. That is, users had the option to add tags to a post, or to up-vote from the tags that were already added. The tag with the most votes was then the primary tag, and all the extra tags were listed in order of votes. This removed the need for the original poster to include a tag, and also allowed for the tag(s) to change if the focus of the thread changed. Unfortunately, I doubt ENWorld has the ability to emulate this feature.
Also, reading a forum by excluding a tag will be an absolute necessity for me to enjoy the change.