I just have some questions i'd like to know for the future if anyone can help?
*why do vice presidents have more responsiblity now than before
*What does the 25th amendment have to do with change?
Perhaps vice presidents have more responsibility because the executive branch has so much more to do because of much higher population and responsibilities.
https://www.law.cornell.edu/constitution/amendmentxxv
When Walter Mondale agreed to run for Vice-President with Jimmy Carter, he demanded to become part of the decision-making process, and Carter agreed. Such has it been ever since 1977. The Vice-President's office used to be in the Executive Office Building; now it's in the West Wing near the President's office. The Vice-President, in the past, was a political decision, to "balance the ticket" with someone from a geographical area the Presidential candidate needed to carry in the election, then quickly pushed aside. Not so much any more. Now, it's someone who can bring some expertise to the table.
As for the 25th amendment, there was no provision in the Constitution to deal with a situation in which the President might be incapacitated. It has happened. Woodrow Wilson suffered a debilitating stroke while in office. Ronald Reagan was shot and almost died, was incapacitated for weeks. A method was desired to deal with such situations, should they arise again. It was a change in the Constitution in and of itself. Now, some people would invoke it, fearing that President Trump shows signs of mental illness. It was not intended to cover mental illness, but could be used in such a case, to provide for a change in leadership if the sitting President was deemed to be incompetent to perform the duties of office without going through the impeachment process.