Many shows from the 60s were rerun in later decades, so there is room to aregue for a 60s section, likewise 50s (classic [email protected], anyone?).
I would suggest the addition of some "...and the rest" section, which could act as a catch-all for anything pre-1970s. Since there's unlikely to be a lot added from any one pre-70s era, it shouldn't be difficult to squeeze it all into one section. Additionally, if you saw that a lot of stuff for (for example) the 60s was being added or requested, then you could spin the 60s stuff off into it's own section.
*WARNING: The above post may be highly opinionated, read at your own risk.