Roswell’s third season is mentioned in an article on io9.com.
They listed 18 television shows that did a total reinvention in their final seasons.
This show dropped a lot of its mythology and became more soap-operatic in its last season, with Max and Liz getting back together and searching for Max’s son, stolen by the evil Tess. Meanwhile, Isabel marries a man she just met and then tries to hide her alien origins from him. Meanwhile, the FBI is closing in on the aliens, until they have to go on the run again.
Read the article in full:
Science Fiction and Fantasy TV Shows That Tried to Reinvent Themselves in Their Final Seasons