weekend updateEven as the controversy continues over the racial diversity of its cast, or lack of it, today’s “Saturday Night Live” seems to be suffering from another angle – the embarrassment of riches when it comes to guest stars who pop in for a moment to take part in a skit.

Usually it’s a familiar face to the show, like Tom Hanks, or sometimes, a walk-on politician (things are rarely weirder than when Presidential candidates jostle to appear). But this week’s show went even further, with its most glittering array of surprise celebrities; whose stars were so bright it tended to eclipse everything else around them.

This week was already a star-packed show, with Jimmy Fallon returning from late night for a second time and typically full of enthusiasm, he was joined by Justin Timberlake. He was only musical guest time but has twice hosted the show as well including once already this season.

He still elicit screams from the audience when he appears, but he seemed to take a step back this week despite his role in his expected skits – the big-handed, pop-singing street barkers and “The Barry Gibb Talk Show.”

But he was upstaged by the roster of stars awaiting their own surprising appearance on the “SNL” stage, first Paul McCartney in the opening Fallon monologue, in which he was going to parody Paul’s style, along with Dylan’s and Bowie’s.

There was a time on “Saturday Night Live” when it was more funny to have Lorne Michaels plead to have the Beatles reunite on the show for a few hundred dollars (“if you want to pay Ringo less, that’s up to you”), because it seemed so absurd that they’d take up the offer. Now, they’re apparently backstage at the ready.

More offbase, possibly, was Madonna showing up in a skit, playing a more matronly side of herself, but not being particularly funny. Then, during the Robin Gibb Talk Show, whose humor is based on the seemingly unfounded idea that Gibb flies off the handle at the slightest provocation, and which seems less funny since Robin Gibb died (would they do a Lennon-McCartney skit these days?),ended with actual Robin Gibb himself showing up,but not having time to do anything.

Finally, if they can’t parody the mayor of New York properly (didn’t Fred Armisen try his hand a couple of times?), why not get him on board as well. He came on with Fallon during “Weekend Update,” which turned into an odd moment of sentimentality and NBC promotion.

Bloomberg was losing his job, yes, but so was Fallon, as he becomes the new “Tonight” show host next year. And so, too, will Seth Meyers, moving into the “Late Night” slot to follow Fallon. And here they were, together as if to pass the torch on a show that in its more insurrectionist days mercilessly made fun of the “Tonight” show concept.

It was all about Lorne Michaels moving his chess pieces around his growing NBC late night empire — he’ll be in charge of 12 hours of programming a week come 2014, more if you count the 10 p.m. “SNL” rerun and the occasional “SNL” prime time specials.

And while all those shows will likely be fine, and better than they have been (except maybe “Late Night”), it seems the staffs might be getting a little thin. The more “SNL” depends on the thrill of unexpected cameos, the less it has to worry about writing something actually funny for these guests to say or do.

When the show relies more on celebrity impersonation — in the “Family Feud” skit that served as little more than a costume party, or in the Fallon celebrity Christmas CD that was essentially a replay of last year’s bit — it’s clear that celebrity faces, real or impersonated, trump material in this “SNL” era.

It makes you think the lucky cast and writers are thinking primarily of the heady after-party and not so much what’s on the screen.