Yeah, there's a huge difference and not seeing it is truly remarkable. If you or anyone else thinks President Obama is going to prop up another Harriet Miers, you haven't been paying attention for the past seven years. Your thoughts above are absolutely moot, the issue is telling a sitting president that he shouldn't nominate anyone to replace Scalia and that the new president should do it. That's insanity, McConnell is dreaming - including the fact he actually thinks a Republican has a chance to win the presidency. McConnell knows that Citizens United will be overrurned and that cases involving immigration and abortion would be rejected - and rightfully so.
SCOTUS, with a 5-4 liberal majority, could very well be the end of the right wing extremism that's arose out of the Bush administration and went postal after Americans elected a black man to two terms in office.
As for Schumer, go fetch a link - if you want to make a point, provide facts to back it up - not doing so is weak and lazy.