I quite like Horror of Fang Rock overall, with a fun sense of characters in a distinct setting, and a very strong sense of atmosphere.  I'd rate it higher but it really feels like we are giving similar plot beats to another season premiere story, Terror of the Zygons, and I much prefer the earlier version with Sarah and Harry over Leela.  I don't have anything against Louise Jameson or her character, she just feels a little more awkward here compared to most other Fourth Doctor companions.  I find the whole bit around changing her eye colours weirdly distracting for something so trivial.  I don't know.  I enjoyed this one overall but can see how this was a start of a bit of a weird season in Doctor Who history.