Why does the Senate do so much business using unanimous consent agreements? In the House of Representatives, the Rules Committee reports a rule governing each measure to be debated, including limits on time and number of amendments. Passage of the rule by majority vote establishes those terms for debate.
In the Senate, prior agreement on the terms and conditions for considering a measure reduces uncertainty and allows more efficient scheduling. But it also empowers any Senator who wants to object for whatever reason -- and often the reason is to get a political side payment on an unrelated matter.
In a piece in the Capitol Hill paper Rollcall [sorry, subscription firewall] , I suggest a rules change that would reduce the number of filibusters, eliminate holds on legislation and nominations, and reduce the need for unanimous consent agreements. That can be accomplished by making the motion to proceed to any measure non-debatable.
As of now, that procedural motion can be filibustered, and over 1/4 of the filibusters in recent decades have been on such motions. The motion is necessary because, under the basic Senate rules, going to the legislative or executive calendars means taking up the oldest item first and disposing of each measure in order. That rule could also be changed, but I think the motion to proceed reform could be a middle ground compromise that allows filibusters on substance but not procedures. The Senate Rules Committee is supposed to be having hearings on the broad question of rules reform later this spring.