I know it had a brief go in the 90s, but I’d love to see a proper adaptation of Animorphs. Those books were wild, especially for something I remember starting in 3rd or 4th grade. I’d prefer animated personally, but I would tolerate another live action series. Tech has definitely improved enough to do the alien races justice in either format. Another pick would be Vampire Hunter D. It got a couple anime movies but I think a series could really do it some justice. It has such a fascinating world.