I'm not sure a fine by the league would keep some situations from getting out of hand during a game. The refs have to keep a lid on things. Perhaps a lesser penalty, plus an enhancement that a second taunting gets a player disqualified in addition to the yardage. As for officials making bad calls, keep in mind these guys get graded by the league. An official's calls might improve through the season owing to the league feedback. And as Jerry Glanville said to one official after a bad call, "NFL means Not For Long, if you keep making calls like that."
If the players get physical, I think there are already penalties that cover that situation. So I do think this is legitimately an attempt to get players to stop taunting. I like your idea of maybe an ejection for multiple infractions. I have concerns that the outcome of games may be affected by behavior that is, in essence, a fleeting and ultimately not-very-meaningful issue of personal conduct. A pattern of behavior, though, is different. And then at least there would be warning, and I think it would be less arbitrary in application if someone (and by extension the team, and the fans) were punished because the ref determined they were disrupting the game, rather than making a momentary gesture that could hurt the other team's feelings.
The real question is what constitutes taunting? If the standard is "it's like pornography, I know it when I see it," then it leads to real issues of unequal application because ya know, language and gestures can only be understood within context and how someone views a speaker can color their interpretation of what was said. A "celebration" by a favored player could easily be seen as a "taunt" if done by a less favored player. And it isn't a black and white call. When the league goes to grade refs, it will be easy to justify the call made in any given example, but in the aggregate, there may be no prevailing standard. And I think the very creation of the penalty is a signal to the refs that the league wants it to be called, so they will be liberal in applying it. It seems very abstract to me in a league where over the top celebration is routine. I think the refs are impartial as they can be, and I do think they officiate the games with integrity, but this is just a powder keg waiting to explode when it costs a team in an important moment. "Why didn't you call THIS celebration as a penalty?" etc ... to me, I'm not sure the benefit of reducing taunting, even if it is achieved by this penalty, is worth the risks to any individual team. Honestly, I'm surprised they would agree to it.
