A closed rule is a restriction that prevents any amendment from being offered when the bill reaches the floor of Congress for a vote. Whenever the majority party wants to get a bill through unamended, they use a closed rule. It blocks minority party influence, and blocks any input from anyone not on the committee that considered the bill in the first place. Closed rules are an important mechanism for maintaining majority party procedural control by locking out the minority party. This is classic "cartel" model legislative politics, as it has been called by Gary Cox and Mathew McCubbins in Legislative Leviathan. Here's the thing, though. Move the bill passage requirement from 50%+1 to 3/5 and unless the majority party has 3/5, you need minority party buy-in to make a closed rule work. In other words, you can't do it. You need to let amendments happen. Does that end majority party procedural control? No. The Rules Committee can still play its games, but this would still be big, if it happened.
Right now, it looks like the Democrats are favored to take the House of Representatives. What does this mean? If these 8 Democrats are sincere, and willing to follow through, Democrats need to win by a bigger margin to get procedural control, or they have to pander to these ninnies. Republicans? Same deal (maybe...). Of course, they might be willing to fold. The whole point of being spineless is that you fold, right? On the other hand, even if the Democrats do win and pander to the disarmament caucus, so what?
Odds still favor the GOP for the Senate, so passing a Democratic bill through the House in the 2019-20 period is irrelevant. A GOP-controlled Senate wouldn't pass any Democratic bills anyway, and even if the Democrats did take the Senate, Donny-boy may be illiterate, but he knows how to write his name, and that means he'll learn how to veto. Same issue. There won't be any successful Democratic legislation through 2020, no matter what the stop-us-before-we-legislate caucus says.
What about the Republican ninnies? They'll cave. If the GOP holds the House by a narrow margin and the speakership contest comes down to their votes, they'll cave. The cartel will hold.
And always remember that congressional rules change over time! The basic issue, though, is that you probably shouldn't expect major rule changes that influence the content of legislation to be determined by 7 or 8 people. Still, this matters. Pay attention.