To be honest, I didn't see Dragon riding going any other way than the on rails method that it is now.
An earlier poster in this thread nailed the reason without maybe actually realising it
We went across low-res Whiterun and all the way to Eldersblood Peak's base where we had a dragon duel and a skirmish with the good folks at Silent Moons Camp.
They couldn't allow free roaming as you could land in the middle of a low res city with no proper cell loaded, the alternative being cities streaming in like the scenery and all but the higher spec PC crying while trying to do it.
This isn't an elitist thing, it is a hardware fact.
The only way to avoid this is to use the method Beth employed with it being on rails.
So whatever your opinions on the Beth team, they chose the option to try and keep quality over quantity this time.
They could probably add a lot more destinations in from what I have heard though (PC so I could't say till I get my hands on it), but they have to keep the flightpath far enough away from cities or have the dragons using very low approach when landing at cities.