Well, if just the Senate flips and either the House or the White House remain in the same party it isn't easy to just flip back and forth. Even when the same party controls all three, it isn't always easy to pass legislation, especially if there are close margins in the Senate or House. So yes, removing the filibuster may sometimes allow the party in power to repeal a law recently passed by the other party. But if one party loses the Senate, House, and White House in an election, maybe that's a sign that the people want the law to be repealed so I'm not sure this is such a terrible thing.
Popular laws are hard to repeal. There is no way the current GOP would pass Social Security or Medicaid or Medicare, but there is no momentum in the party to actually repeal any of these things even if they controlled the House, Senate and White House. I guess I see the benefits of being able to pass needed legislation as far greater than the detriment of slightly more uncertainty about whether a particular law will last for the long term.