First off, the "worst VMK idea ever" was when they lied about the parade event last summer. Not only was it a sorry non-event, but the powers-that-be clearly, and some say purposefully, misled players into thinking that a parade would occur on Main Street. That event forever tarnished the trust that hundreds of players had for the game and its designers. Thus, it was not just a bad idea, it had historical importance for the game by creating a credibility gap that has only widened with subsequent mistakes. (Before challenging this, read your VMK history books.)
Now, about this line-limitation. It seems the arguments against it consist solely of:
1) I don't want to have to try to get in a line more than once, and
2) I want to be able to walk away for up to an hour while I wait in line.
Regarding the latter argument: this walk-away tendency was one of the things that made the room events difficult. Players would be afk when their characters entered the room. Those "afk characters" then took up limited occupancy space in the room. Going afk may have been a convenience, but it was a serious hindrance to others who were actually in line, waiting to play, fearing the disconnect all the while. The new line-limit provides a mild corrective to this problem.
And in regard to the first argument: well, there is no medical cure for the modern desire to have everything we want, when we want it.
Doubtlessly, complaining about VMK has become a great DIS pastime. But complaining about many things, like this improvement, will only diminish your complaints about the very awful things. Like the parade event!
Ricks