Every change means more headaches when the bill goes to reconciliation between the two houses. That’s one of the big disadvantages of a bicameral legislature—there’s a strong disincentive to fixing problems by the time a bill gets out of committee, which means if you’re not on the committee, you usually have little to no say unless the problem with the bill is grave, in which case enough people vote against it (you hope) to keep it from passing, and the committee has to rethink it.
This also points to a serious flaw in the way committees operate. Instead of a committee consisting of everyone with an interest in an issue, with open discussion, the committees are carefully selected groups consisting of a proportional number of members of each party, and are not necessarily the people who are most interested in that particular issue, but rather the people who are ostensibly most interested in the broader topic of the committee (at best). This is pretty much the exact opposite of the way that things should be done, assuming the goal is to actually pass the best, most reasonable bill possible.
So yes, the entire system is pretty much broken from top to bottom, to such a degree that progress is always made in spite of the system, never because of it. And that’s part of the reason so many bills end up being basically prewritten by lobbyists.