CBS does well with their schedule of dramas, airing shows with ratings that smaller networks would kill for. That popularity means even series with impressive numbers of viewers can get cancelled. When the network made their final announcements about the fate of their scripted series, they renewed five “bubble” shows that many critics expected to be axed.

Syndication deals and schedule needs often dictate these renewals. These five shows need to make changes, however, if they hope to avoid the ratings drops that put them out of business for good.

1. “The Odd Couple”

The reboot of this classic TV series has done okay for CBS, but the numbers keep slipping. With fan favorite Matthew Perry in the lead, this series is worth pursuing for another season to see if viewership can tick up again. CBS wants to maintain their block of Thursday comedies, and decided to keep a known entity alongside “Big Bang Theory” and “Mom.”

The funny thing about the beloved “Friends” veteran is that he’s the weak link on the show. Thomas Lennon attacked his Felix role with gleeful abandon, incorporating a wealth of physical comedy into his stuffy roommate routine. Yvette Nicole Brown, Wendell Pierce, and Lindsay Sloane round out the delightful cast, delivering witty one-liners and amusingly awkward situations.

Perry, while still lovable, seems to be too caught up with the live audience. He delivers lines more like a stand-up comedian, with stilted body movements and a loud stage voice. The lines are funny enough to make it work, but it doesn’t mesh with what the rest of the cast is doing. The actor has improved since the premiere, and hopefully next season he’ll be able to win over viewers with a little more nuance in his performance.

2. “CSI: Cyber”

CBS pushing “Oscar winner Patricia Arquette” on its latest installment of the “CSI” franchise seems more ironic than promotional. Fans are familiar with Arquette’s often monotone and unsympathetic demeanor from “Medium,” a show that was successful almost in spite of its lead. A serious, monotone role on this series seemed like the right move, but often highlights her limited range.

The new series hasn’t done very well with critics or viewers, but with the mothership “CSI” ending its run, CBS wants to fill the void with this spin-off. In an effort to increase its popularity, the network has already begun reworking the series. “CSI” veteran Ted Danson will move to the cyber division next season. Peter MacNicol won’t return, giving Arquette’s Avery Ryan more autonomy in a supervisor-free environment. Improving the confusing, sometimes corny writing would also help this fledgling series.

3. “Elementary”

This modern-day Sherlock Holmes reinvention seemed destined for greatness. After some early skepticism about toying with a classic, both critics and fans embraced the series. Season three lost a chunk of viewers, with the season finale at 14 percent lower than last year’s. This series likely avoided cancellation because a four-year show leads to a lucrative syndication deal.

Like many dramas that falter, “Elementary” played around too much with its core formula. Fans tuned in each week to see Holmes (Jonny Lee Miller) and Watson (Lucy Liu) interact as colleagues and friends. Season three saw them estranged, and often working separately. Holmes even had a new protégé, Kitty (Ophelia Lovibond), who had more screen time with our hero detective. When the series finally mastered them as a dynamic trio we enjoyed, Kitty left.

Holmes succumbed once again to his drug addiction in the finale. Season four could reboot to the series’ beginning, with Watson acting once again as counselor as well as partner. This is a risky plan. Fans will be happy to see the two drawn closer together, but reliving the eccentric detective’s heroin struggles may prove to be a journey viewers don’t want to take again.

4. “The Good Wife”

This critical darling is “on the bubble” every year, but escapes the guillotine for another season. The series shed viewers steadily through season six, dropping about three million before a slight surge for the finale. Ratings are tricky for this drama, as its Sunday-night slot causes random start times after unpredictable sporting events.

It seems clear that fans weren’t thrilled, however, with “The Good Wife” mixing its formula up this past season. Alicia (Julianna Margulies) ditched the courtroom for a political career and seemed to forget she had a family. Diehard viewers also didn’t appreciate how the series arbitrarily changed character motivations and insulted Will’s (Josh Charles) memory. The final episodes got Alicia out of the politics race and back to law, and indicate a clean slate for season seven.

The main cast signed on for two more years, though a season eight is unlikely. The series doesn’t make the desired target demographic numbers that networks like, but the show has a loyal and engaged following. It currently makes sense for CBS to keep a show that retains a dedicated viewership in a difficult timeslot, grants the network prestige, and makes money for them in syndication.

5. “Person of Interest”

You know you’re in trouble when your finale numbers are series lows. Season four ratings were a roller coaster. The random schedule of skipped weeks hurt viewership on each return, before slowly building again. Like “The Good Wife,” this drama about an all-powerful Machine has a diehard fan base. The discouraging news about the renewal is that so far, it’s only for a 13-episode order.

Showrunners Greg Plageman and Jonah Nolan have big plans for season five of “Person of Interest.” The Machine’s essence was downloaded into a suitcase in the finale, so our favorite characters’ world will be quite different going forward. Two major character deaths hurt the series viewership, so more big changes might not be a good thing.

The hook of the show was about a dangerous world where a misfit group of characters tried to save lives. There was a hopefulness about it. We enjoyed seeing our clever, tough heroes take down the bad guys. With Samaritan and this new world order, viewers are feeling a lot more hopeless. Plageman and Nolan plan to get our Machine up and running again, and they’ll need to if they want to keep fans tuning in.

These five series all began with great potential, and still have hope for a prosperous future. Some strayed from what got them fans in the first place. The newer shows struggle from some acting woes. Those performers can hopefully settle into their characters and produce better results. A few writing tweaks can help the long-running series appease their fans. It’s not easy to stay alive on CBS, but these shows all have a shot.