Gene's lawyer, Leonard Maizlish, must've been a pretty nasty individual. I've never read a single positive thing about the man.
Not one positive word in any of the books I've read.
Not to unduly defend the man (or cast any negative aspersions on the legal profession) but I think most (if not all - did Fontana ever publicly comment on Maizlish's involvement in TNG?) of the bile seems to have come from Gerrold, stemming from his treatment by Roddenberry during the development of TNG. Gene was just being Gene, co-opting credit for ideas that clearly had Gerrold's fingerprints all over them (many dating back to his "World of Star Trek" book in the early '70s). I'm not a Gerrold fan ("Tribbles" IMO overrated and he comes off like a bitter Harlan Ellison wannabe, in temperament if not talent), but he should have been given more credit (and probably compensation) than he got for his work developing TNG. He just unfairly got caught up in Gene's consolidation of his business interests in Trek, which at that point centered on TNG.
For better or worse, Maizlish was hired by Roddenberry to protect his newly reestablished interests (both creative and financial) in Star Trek after being unceremoniously bounced from the films forevermore after TMP. His involvement necessarily increased as Roddenberry's mental and physical capacity diminished; Maizlish was then dutifully (if perhaps overzealously) protecting the Roddenberry estate's stake in the Star Trek property, with Rick Berman, et al. looking out for Paramount's business interests. Just business, but Gerrold took it personally. He didn't want to risk alienating fandom by assailing the Roddenberry legacy, so Maizlish became his target.
Gerrold's issues with Maizlish seem to transcend professionalism and devolve into personal resentment that he, a
professional writer, was being forced to collaborate creatively with this
lawyer (ever see Alec Baldwin's dripping reading of the word in the film Malice?).
I highly recommend the "Discovered Documents" section of the Mission Log Podcast site; there you will find some very candid and revealing memos from the period, including some from Maizlish. I found one from 1987 (so around the time of Gerrold's issues with Maizlish) regarding TFF particularly interesting. It's the second one on the page and incorrectly attributed to "Paramount Pictures", but it's clearly Maizlish prepping Roddenberry prior to a lunch meeting with Shatner over the TFF story:
http://www.missionlogpodcast.com/discovereddocuments/095/
Note how the memo is from "LM" and not "Leonard Maizlish", perhaps anticipating future WGA scrutiny of his involvement with the creative side of Trek as eventually happened (undoubtedly at Gerrold's prodding) as can be seen in the first and last memos here:
http://www.missionlogpodcast.com/discovereddocuments/118/
From his TFF memo, Maizlish clearly "got" the core creative problems with the story that survived all the way through to the released film two years later. He's even pointing them out to Roddenberry himself; by comparison Roddenberry's memo is rather rambling and unfocused ("Can we talk?"), with something about "religion and God" and "what has been happening to public attitudes in that area" (whatever that means). He seemed to "get" Star Trek as well, at least in the way Gene envisioned it.
Just goes to show that there are still many untold stories behind the scenes of Trek; Maizlish's contribution to Trek may remain largely unknown now that he, Gene, and Majel are gone. Did Susan Sackett discuss Maizlish in her tell-all?