I love the Koroks and Ritos but I don't see how they could fit into the game. Ritos and Kokiris are the evolved form of Zoras and Kokiris. They evolved around the time of the Great Flood and since this game takes place way before OoT at/near the beginning of the timeline, it just doesn't make sense. I think it's unlikely we'll see the Deku tribe because the only game that they were really a civilized tribe in (to my knowledge) is Majora's Mask. All other games they've just been common enemies or business scrubs. That was in Termina, not Hyrule.
I'm not a huge fan of gorons but I think that a game without them would feel awkward for me, so I voted for them. I also voted for the Sheikah, Zoras, Kokiri and something new. Sheikah because it just seems to work well and would please fans. I know almost everyone loves Sheik and would love to see an entire Sheikah tribe. I could see Nintendo adding them in as a fan service. I think it would work well because OoT was right after the end of their tribe and since this game comes before it, I expect to see them. The only argument I've heard against this is that Impa created Kakariko Village for the Sheikah and she's not hundreds of years old. That just means that Kakariko Village wasn't there. To my knowledge, that doesn't necessarily mean that the Sheikah weren't around. Correct me if I'm wrong. I'm hoping to see the Kokiri since I want to see a forest tribe, and I can't see the deku being one, since they are only civilized in Termina. I expect Zoras, as well. I'd like to see a new tribe since every Zelda game seems to have a few new ones. OoT brought Sheikah, Kokiri and Goron. MM brought Deku. WW brought Koroks and Rito. TP brought Oocca and Twili. I don't see why this one won't have any new races.