My opinion is to make the filibuster a “break in case of emergency” that has actual tangible consequences. Conceptually it becomes something that any senator is allowed to do, but anyone who participates is removed from office regardless of the result of the vote and are barred from holding any office. For me, they are taking extreme action based on some equally extreme personal moral objection. That is valid and should be allowed, but actions have consequences and the consequence of imposing your personal morals on the governance of the people is that you no longer get to participate in that governance. You have to feel so strongly in your convictions that you are willing to sacrifice your entire political career to take the action.