Jay Leno and Jimmy Fallon

Jimmy Fallon just celebrated his 800th episode of Late Night.

He's been on the air for four years, and NBC already wants him to host the Tonight Show.

In terms of late night TV, that's a quick rise. It took David Letterman more than a decade to get a show in that time slot.

I'm a late night TV viewer. I have been since I was old enough to determine my own bedtime. I've seen the hosts come and go, rise and fall, entertain and annoy.

I used to be a Letterman fan. I thought he was destined to be the next Johnny Carson, but NBC chose a different direction and went with Leno as Carson's successor.

Conan O'Brien's brief stint as the next Carson was a mess. I loved O'Brien's Late Night, but his show lost a lot when he moved to LA. The enormous studio didn't suit him. Something was very off. I still liked him better than Leno.

So, Leno returns to Carson's chair after a bitter fight. No one came out of that one looking good, except Jimmy Fallon. He, publicly, stayed out of it.

And now, NBC is ready to give Leno the boot again.

Good idea or bad idea?

From FOX News, the outlet routinely trashed by both Leno and Fallon:

Will Jimmy Fallon be the next host of “The Tonight Show?” He says he doesn’t care.

In the latest issue of GQ, on newsstands March 26, the funnyman addressed the burning question of whether or not he will take over “The Tonight Show” after Jay Leno retires.

“I mean, in the nicest way, who really cares,” he told the magazine. “In the nicest way. It would be great, sure, I guess. I’d love it, but it’s not on my mind. I’m in no rush to do anything. I’m kind of a boring character in that book. I’m not in a fight with Jay or Conan, or any of them. I don’t have that story.”

Still, “Saturday Night Live” producer Lorne Michaels said he thinks Fallon is a shoe in for the job.

“I’m not allowed to say it—yet. But I think there’s an inevitability to it,” he told GQ. “He’s the closest to [Johnny] Carson that I’ve seen of this generation.”

I still consider myself to be a fan of Fallon's show, though he has shifted away a bit from his goal to entertain without alienating people. That's unfortunate.

As much as I like Fallon, he's not close to Johnny Carson. He's irreplaceable.

Letterman, although from the midwest, didn't have the midwestern charm of Johnny Carson. Letterman's style is snippy and smart ass, and incredibly grating after a while. No Carson.

Leno seemed like a nice guy and appeared to want to appeal to a broad audience, but he's taken a sharp Left in his comedy and interviews. Also grating. No Carson.

O'Brien was really clever and quick and likable. His self-deprecating humor was funny, until it became impossible to accept as based in something honest.

None can compare with Carson.

Fallon is extremely talented and can be very entertaining. However, I don't know that he'll appeal to an older demographic. Yes, he won a Grammy and did a fantastic job hosting the Emmys. But at least some of what he does now would have to change. For example, I don't think an older audience would enjoy watching him debut a new video game. The goofy stuff probably won't translate well.

From The Hollywood Reporter:

It has become clear that Jimmy Fallon is going to become the host of The Tonight Show, but sources say an internal debate among key players is underway regarding the timing.

According to these sources, some top executives at NBCUniversal are leaning toward a February launch to take advantage of the promotional platform of the 2014 Winter Olympics in Sochi, Russia. Others, including Late Night executive producer Lorne Michaels, are said to have concerns about rushing the transition.

The Leno-Conan debacle is still relatively fresh. Another retirement against his will by Leno wouldn't be too pleasant. Here we go again....

NBC Entertainment chairman Bob Greenblatt and his late night and alternative chief Paul Telegdy are said to be actively looking for a Fallon replacement at 12:35 a.m. One possibility is another Michaels protege, Seth Meyers of Saturday Night Live.

The latest news comes as Leno continues to take jabs at NBC execs including Greenblatt, who reportedly sent Leno an email to back-off on the ridicule. On Monday’s show, Leno quipped during his monologue: "You know the whole legend of St. Patrick, right? St. Patrick drove all the snakes out of Ireland -- and then they came to the United States and became NBC executives. It's a fascinating story."

Leno taking jabs at NBC execs should be no big deal. Carson regularly mocked the execs behind NBC's programs and the network's poor performance.

I wish Leno, and all of these late night hosts, would make fun of the PRESIDENT OF THE UNITED STATES. I like to think Carson wouldn't have given Obama a pass or been a shill for Obama, like Letterman and Leno. Fallon is possibly the worst shill of all. He let Obama use his show like no U.S. president has ever used a program in a network's entertainment division.

I certainly won't miss Leno when he gets shown the door - again. Good riddance.

If Jimmy Fallon takes Leno's place as expected, I think I might end up missing the Jimmy Fallon of Late Night, just as I missed the Conan O'Brien of Late Night and the David Letterman of Late Night.