That's true, Forza is a very fine game. And the map itself is quite refined and detailed. But it is too small for cruising, we did try with a friend but it became boring real quick. On the other hand The Crew - game supposedly created by the guys previously working in Eden - game that has absolutely uninspiring driving model and a big map. But at the same time this map seems kinda bland. Not all that refined, giving some vibes of the USA but lacks at quality. Nevertheless I did spend quite a lot of time in both the Horizon series and TC and had lots of fun. Just none of them gives me all that much fun when cruising.
And this I believe is the biggest challenge for them. Creating a game with satisfactory driving model, with map large enough to not be boring after a couple of drives while also quite detailed. Honestly my hopes are really low after TDU2 and TC, but afterall Kylotonns WRC series is getting better and better each instalment, even when the post release support is somewhat lacking. I'm rooting for them but not expectiong miracles :D