In Grand Prix mode, you can create a season of any length and any order, I believe? That's been the closest I think it's been.
It used to be that if you chose custom season in MyTeam then you could edit tracks that appear from the second season onwards but I don't think you could change the order? Now that France and Portugal have gone and China has been incorporated, it has left just the reverse tracks which i'm not sure many people would put into their calendar... probably. So I did wonder what custom calendar would mainly be used for but i've not finished the first season of MyTeam to find out.
It would be good to change the order, but I expect it'll be said that the tracks have a certain place on the calendar due to licensing and realism. (for example, you'd not likely be racing in a harsh winter, or roasting hot summer, in some countries). That being said, it's a game where you can drive as Brad Pitt when he's like 60-odd years old, so I guess there is some suspension of disbelief.
I've not used the rewind function to actually rewind yet, but I went to use it for camera mode and noticed the flashback motion looked like *** now so quickly jumped off it and haven't used either the replay or camera mode yet. I don't think they'll revert it, but if enough people say they're not a fan then they may do.