There are a number of websites (iMDB.com, StarTrek.com, etc.) that mentioned Andrew Robinson almost got the part of Odo in DS9 after his first read. Garak was my favorite character in DS9. I dont think many actors could pull off what Andrew Robinson did for Garak. That being said... How different would it be if Robinson played Odo? Let us call it an Odo-Rob, and the original as Odo-Aub. Since Robinson helped develop the Garak character, we may have gotten a hybrid Garak-Odo character -- consisting of Odo-Aub and Garak. Yet Robinson is a talented actor. Perhaps Robinson may have given the audience a completely different version of Odo. What do you think?
The gruff speaking voice was Auberjonois' invention, and unlike his natural voice. So interpretations would have been different.
I do believe Odo-Rob would be darker and slightly more mysterious character than the original. Robinson might have delved in deeper the differences between changlings and solids -- lifestyle, viewpoints, etc.
He wasn't writing the scripts. Only interpreting them, and inspiring the writers to keep developing Garak.