I'm trying to imagine myself exiting Egypt and arriving at Matan Torah. I expect that for 49 days the Jewish people expect G-d to give them something they didn't already know. Instead, G-d recites the 10 commandments that are already well known:
אנכי + לא יהיה - self-apparent, repetition of Pesach
שבת + כיבוד אב were given at Marah
לא תרצח, תנאף, תגנוב - very old
לא תשא + לא תענה + לא תחמוד seem new.
I value the magnitude of the event and people having an unimaginable experience of seeing their G-d, but information-wise I can't see many Chiddushim here.
From the Mitzvos point, what were the big Chiddushim of the 10 commandments?