Nozomi was always excluded on JR Rail Pass. Nozomi has slightly higher Shinkansen Express Surcharge (新幹線特急料金) than Hikari or Kodama, although difference is only few hundred yen. This was a reason (or excuse) for excluding Nozomi from JR Rail Pass.
It was not a problem when Nozomi started with only early morning and late evening service between Tokyo and Shin-Osaka. Today there are more Nozomi than Hikari most of the day but the surcharge fare difference still exist between Nozomi and Hikari/Kodama. Hence Nozomi is still excluded from JR Rail Pass.