Clinton will push for raising the cap on social security contributions as a primary way to adjust for changing demographics. This is an excellent way to adjust. She may also push for a small increase in the contribution rate. The Trustees, several years ago, were requesting a 1 cent employer/employee rate increase. Haven't looked to see if that figure has been adjusted up. I suspect it has, since Congress failed to act in a timely manner on the Trustees recommendation.
There will likely be a push to modify Obama care: On the table will be the Public option again (a step toward single payer!), and making health care access independent of employment (should have been that way to begin with). There may even be a push to repeal McCarran- Ferguson, which would be a giant leap forward.
Whether anything can be accomplished is going to depend on the make-up of the House and Senate after the election. Vote democrat if you want to see Obamacare fixed and a balanced budget. The democrats will raise taxes a small amount, a few percent probably graduated, on high income families and individuals, but not by as much as is needed. They will not raise taxes on ordinary incomes other than the possible exception of a small increase in the payroll tax. Remember that that portion of the payroll tax that goes to Social Security is, for the vast majority, an investment rather than a tax, i.e., the ROI, on average, is positive. Vote Republican if you want low taxes and more 'defense' spending, i.e., dramatically higher deficits, and eventually higher inflation and long term costs.
The democrats won't put much of a check on wasteful DOD spending and harmful, useless wars, but they will be much better at holding the defense industry in check than the Republicans. If you work for the defense industry, vote Republican, if not vote Democrat.
The democrats and Republicans will both push for immigration reform, but they won't agree on how to do it. The Republicans will block every Supreme court nominee until the exasperated Senate Majority leader changes the rules to prevent a further filibuster on court nominees. The Republicans will cry "foul." despite having left the Democrats with no choice. In this way, the Republicans, having blown their chances to agree on a less "liberal" appointee, are guaranteed to get a rotten appointee, from their perspective. Could even be a black or an Hispanic or possibly a 'communist' female.. Vote for Trump if you want to keep 'horrible' people, like women, off the court.
The Republicans will continue their scorched Earth policy and do what they can to make a mess of any democrat initiatives and legislation that might squeak through.