Most of the Metal Hero main writers have also be involved in the sentai franchise, so I'm gonna focus mostly on their Metal Hero work :
Shouzo Uehara : He's the one who has been the first main writer in the Metal Hero franchise, which he involved himself into after leaving the sentai franchise. He's been the main writer of the first five Metal Hero shows, the Space Sheriff trilogy, Juspion and Speilban: he's the one responsible for the whole "Space sheriff and similar shows" era: After Speilban, when the franchise tried new ideas, he left, only writing one episode of Metalder and, much later, one of Blue SWAT. As head writer, Uehara writes most of the episodes of the shows he's head writer (even all of them in Shaider)
Susumu Takaku : Takaku had been seondary writer of Uehara when they were working in sentai ( and they were both head writers of Battle Fever). Takaku remained as secondary writer of Uehara in the early Space Sheriff shows (Gavan and Sharivan). After Uehara left, he became head writer of the two following Metal Hero show, Metalder and Jiraiya, two shows that would try new formulas in the franchise, but both shows are pretty much unique in the franchise. He remained as secondary writer in the three Metal Hero shows which had Noboru Sugimura as head writer, then left the franchise at the same time as Sugimura. Unlike Uehara, and like Sugimura and Miyashita, Takaku only writes about half of the show he's head writer, leaving many secondary writers to be involved in many episodes.
Noboru Sugimura : Sugimura had written a few episodes of Spielban and Jiraiya, but he became head writer with Jiban, and he's the one who started the "urban cop" Metal Hero concept. That concept would be improved in the two following shows, Winspector and Solbrain. Those shows ar ethe two first series of the "Rescue Police" trilogy, which really had been groundbreaking in the Metal Hero franchise. After Solbrain, Sugimura left the franchise to work on the Super Sentai franchise, where, once again he was involved in groundbreaking shows. Like Takaku, he only writes less than half of the episodes himself (in Winspector, he only wrote 13 episodes out of 49)
Junichi Miyashita : Miyashita started as a secondary writer in the two first "Rescue police" shows, Winspector and Solbrain. When Sugimura left the Metal Hero franchise, he took over as head writer in the Exceedraft, the last show of the "Rescue Police trilogy" and stayed as head writer in the four following shows, Janperson, Blue SWAT, B-Fighter and B-Fighter Kabuto. It's during his run as head writer that Metal Hero once again tried a completely different concept with the B-Fighter shows.
Interestingly, Miyashita would be later involved in a sentai show with a rescue theme as secondary writer (GogoFive) and in his sentai shows as head writer, he introduced insect themes warriors (the Gouraigers in Hurricanger). He writes a little less than half of the episodes in series he's head writer of (he would do it again in Hurricanger); besides, during his "Rescue Police" era, he often co-wrote episodes with other writer, most notably Yasuyuki Suzuki, with whom he wrote a good bunch of episodes, notably final arcs of series. He stopped working with a co-writer starting with B-Fighter.
Some secondary writers of note:
Nobuo Oogizawa: he started as secondary writer in Metalder, and then, stayed as secondary writer during all the remaining shows of the Metal Hero franchise, usually writing between 7 and 10 episodes for each series (even 14 in B-Fighter) : he's pretty much to the Metal Hero franchise post-Uehara what Kunio Fujii was to Hirohisa Soda in sentai.
Speaking of Kunio Fujii, he's an important secondary writer during the "transition era"; he left the Metal Hero franchise soon afterwards, only writing one episode for Winspector.
Another important secondary writer is Kyoko Sagiyama (a fromer secondary writer of Soda in sentai), who started as secondary writer in Winspector and then stayed as secondary writer in all the following shows, usually writing about 3-6 episodes for each show.
Some last interesting trivia: Yasuko Kobayashi was involved a ssecondary writer in every Miyashita Metal Hero show starting with Janperson : both would be involved as secondary writers in GogoV.
浅香晶 has been also an important secondary writer for Miyashita, also starting as a secondary writer in Janperson, and involved in every Miyashita penned Metal Hero show since.