Actually, in political discussions when JFK comes up, I always mention that with the policies he had at the time, today he'd probably be a Republican. He was also a Life Member of the NRA, FYI.
First, I'm not as big a fan as you seem to be, and I did write an essay on Kennedy, too. Here's the link:
http://viewfromtheisland.townhall.com/g/7f574461-61cc-4716-ba81-dc424c8691f5I don't really want to re-open conversation at that essay, it's there simply for reference, and to make the point that I considered him a very mediocre President. I well remember his Admin, as well as LBJ's.
Without the Kennedy assassination, there would have been no GCA '68, and gun control wouldn't be the issue it is today without the fulcrum of the JFK, RFK and King hits.
The Great Society was, indeed, an LBJ invention, arising out of his Southern guilt for past racism I'm sure, as was also the perception at the time. He'd tried to push that stuff as a Senator, too, got nowehere, so used the Bully Pulpit of the Presidency once he inherited the office.
Also, at the time of the JFK admin, Reagan was more liberal that where he ended up as President; he evolved. JFK may have, too, who knows? Those guys of the WW2 era had a clearer understanding of world realpolitik than their successors, from Carter onward, which is why we've had such mediocre-to-awful Presidents from Carter onward. That's no coincidence. Reagan was the last of the WW2-era vets.
That having been said, I'll now say I never liked the guy, for many reasons. First, his Presidency was one of ineptitude. Bay of Pigs, where he pulled all air support at the last moment, deserting the Cuban Freedom Fighters to a massacre. He almost stumbled us into a nuclear war over the Cuban missiles because of obsolete missile bases we had in Turkey (outlined at the linked post), and only lucked out of that one, almost in spite of himself. That was a VERY scary time. He was politically cynical, using his brother Bobby as a Mafia-like political hitman. His very hypocritical exploitation of Sammy Davis Jr, outlined in my linked post. His moral turpitude, facilitated by the MSM's complicity and willful blindness, were also problematic. He authorized the assassination of Diem, head of state of an allied nation, and started our involvement in Vietnam.
Sooooooo, there you have it. He had some successes, but they're almost of the blind squirrel variety.