Batman returned to CBS after 7 years away in February 1977, even though reruns of Super Friends were still airing on ABC at the time. The series cycled though in reruns on CBS until 1980, when it moved to NBC for one last cycle. The fact that rival Hanna-Barbera held a license of their own for the DC characters, one that would be renewed a few months after New Adventures launched, precluded Filmation from moving forward with a 2nd season.
There were a number of changes:
1. Villains: Even though he was included in the open, the Riddler wasn't used, as he'd been acquired, along with Scarecrow, by H-B, and would return in Challenge of the Super Friends the next year. Made-for-TV foes from the 1968 series, Simon the Pieman & The Judge, were not brought back. Instead, new villains were developed in the form of Sweet Tooth, Prof. Bubbles, Electro (not to be confused with the Marvel villain of the same name), and the Moonman.
2. Character designs: The only cosmetic changes were on three characters. For starters, Police Commissioner James Gordon was given the same look he had in the comics, with silver hair and a mustache, as opposed to being clean shaven & brown haired 9 years earlier. Robin's costume tunic had been color-reversed to avoid confusion with the Super Friends model. Catwoman traded in her green turtleneck jumpsuit for a brown leotard & tights, and her hair color changed from black to brown as well. The Princess of Plunder got the worst of the deal.
3. Casting: The big selling point, of course, was the return of Adam West & Burt Ward as Batman & Robin. Filmation needed to recast the leads with Olan Soule & Casey Kasem now at H-B. The studio's leading lady, Jane Webb, however, was not brought back to reprise as Batgirl & Catwoman. Instead, a relative newcomer, Melendy Britt, stepped in, as Webb was being phased out. Webb's last Filmation job was the Archie-Sabrina Hour for NBC in the fall of '77. Also, with Ted Knight wrapping up The Mary Tyler Moore Show, and seemingly retired from toons (his last Filmation work was Lassie's Rescue Rangers), veteran writer-actor Len Weinrib took over the roles of Gordon, Joker, Mr. Freeze, & Penguin, in addition to various subordinates and the new villains. His Sweet Tooth voice, for example, was a riff on Paul Lynde, and, as noted before, his Moonman might have been partially inspired by Casey Kasem, but not all the way. Co-executive producer Lou Scheimer went uncredited as the Bat-Computer, various incidental characters, and Bat-Mite, the 5th Dimensional imp whose attempts at aiding the Masked Manhunters were disasters waiting to happen, counter-balanced by his crush on Batgirl. Weinrib voiced the villain Zarbor, who came from Bat-Mite's world, and appeared in the final 3 episodes. Scheimer would recycle and modify his Bat-Mite voice for Orko (He-Man & The Masters of the Universe) just 5 years later.
In addition, in keeping with the comics of the day, Batgirl's dual ID of Barbara Gordon was known to the Dynamic Duo, and otherwise, Barbara was now an assistant district attorney, in contrast to the books, where she had been elected to Congress, a role she'd have until the early 80's. Also, as noted, while Bat-Mite carried a torch for her, in the books, Batgirl had to deal with Robin developing a similar crush that would lead to an on-again, off-again romance. Shoot, they'd even discussed marriage at one point. Bat-Mite couldn't be that lucky, even if he tried.
Some of the incidental music, composed by Ray Ellis (under the dual pseudonyms of Yvette Blais & Jeff Michael, which Ellis used at Filmation throughout the 70's), was lifted from live-action shows such as Shazam!. Like, couldn't they afford new music?
To refresh your memories, here's the open & close: