I was just reading a walkthrough for hgss and saw the whole list of legendaries and wondered if it had more than emerald...
Note: Event Pokemon are not included. They wouldn't make a difference anyways.
The only Pokemon you cannot get in HG/SS that were in Emerald were the Golems (Regice, Registeel, Regirock). So HG/SS had more.
HG/SS is your answer.
Emerald has more legendaries.
Emerald has 10 legendaries and HG/SS has 6.