But it's already diverged enough IMO to warrant enjoying them separately. Might as well get the full experience... Plus without the source material to work from I'm skeptical as to just how great the TV ending will be. But I guess we all take what we can get at this point.
Yes, it's almost like "One Flew Over The Cuckoo's Nest" divergence level at this point. The movie/show and book(s) are both excellent but tell very different stories.
Douglas Adams changed HHGTG for each medium. Whether from boredom, appropriateness, craft... I dunno. But I do know that I love each retelling on its own merits.