This may be a controversial idea, but i think it would be really cool to play as a Templar. Rogue gave us a taste of that and to be honest I thought it was a lot of fun.
I get a sense that this might be the direction the franchise is going with the ability to choose in Odyssey. I have 3 Ways that I would like to see Ubisoft expand the Assassin's Creed franchise and allow us to play as a Templar.
1: A game where our choices dictate the outcome of which side we are on.
Since Odyssey takes place before the Brotherhood as we know it, this may not be the exact formula we will see in Odyssey, but I think it would be a lot of fun to see a game that lets us determine which faction we end up comitting our alegiance to.
2: Expand the universe to allow Other games to fit into the franchise like a Templar Order Game. Since there was series Fatigue from it being released every year, perhaps having an Assassin game one year and a Templar game the next. Perhaps even expanding behond that to include a true moder day only game, or an Isu game or other factions that could be included.
3. Develop a game where we select which side we are on right from the start. We could see the 2 selectable characters chasing after one another and interact and see the story from opposing views. Alternatively it would be neat if you play the Game as an Assassin, and kill certain Templars in a specific order, when you play as a Templar you see them fall in that same order and what might have been the original intended storyline is affected byt the first playthrough.
Anyhow these are some ways I would love to see Assassin's Creed expand the universe and allow us to play as a Templar on a more consistent basis.