According to the LA Times, fans shouldn't be worried about the departure of Swimmer and Slaykin:

While the show has yet to be renewed for a ninth season, sources assure that a greenlight for more is likely. And with Swimmer and Slavkin gone, the show's other two executive producers, Kelly Souders and Brian Peterson, are poised step in as show runners.

But while the producers may be in place, what about the actors? Rumors are still going around that some of the cast — including Clark himself, Tom Welling — are uncertain about signing up for a ninth season of the show, and last week fansite Kryptonsite suggested that the CW may be thinking of alternatives:
[W]e are starting to hear rumors that if Tom does not sign for a Season 9, there might be a Smallville spin-off in its place after all. No ideas yet on casting or concept, or if this is anything more than a rumor, but it's something to think about...

A spin-off? Even though recently proposed Robin-centric spin-off The Graysons didn't make it past the drawing board? Really, people. If Welling doesn't want to continue for a ninth year, don't think about new showrunners, don't think about spin-offs. Just let the thing come to a natural conclusion already.

'Smallville' producers set to helm 'Melrose Place' reboot [LA Times Showtracker]

We can't help but feel somewhat sad for poor Marc McClure. The guy has to play the hapless dork Jimmy Olsen in several Superman movies, and then Smallville rolls around. Season after season of the show goes by, and he sees Christopher Reeve, Margot Kidder, and even the freaking voice of Terence Stamp appear in the show. More than that, they've got Superman III (shudder) star Annette O'Toole playing Martha Kent. But does poor Marc get a call? No. Finally, Season Seven. His big shot in the spotlight. Hooray! We imagine the call went something like this:

Marc? It's your agent, Morty. You'll never guess, but the Smallville folks called up today, and they want you on the show. Yes, I know! It sounds great, doesn't it? What'll you be playing? Oh, you're Dax-Ur, a sort of dorky Kryptonian who created Brainiac, a good-looking robot dude who destroys worlds! Hmm? Yes, yes, you're Kryptonian. What's that? Do you fly around and punch the crap out of people? Um, no. You've given up all of your powers and you wear a blue kryptonite bracelet... hello? Marc? Hello?

Sadly, it doesn't look like Marc will be returning to the ranks of Smallville, based on the clip below. But if you're going go, why not go in style? Having Brainiac shove his massive Terminator 2 liquid metal-style finger deep down into your neck isn't the worst. Plus he can download your brain with that same finger, which is pretty useful, and probably a fun party trick. Bizarro with his crystallizing face in one corner, and Brainiac with his phallic finger in the other. Set up a keg, and you're good for at least six hours.