Firstly, it's Milestone at the helm. Secondly, its being designed.built in Unreal 4. The first part has me not setting my expectations too high but the second part is a great move.
Just looking at the MXGP offering they released using U4 was a nice step up from earlier versions. Also you just have to look at Assetto Corsa Competizione which is Kunos's first foray in to U4 and it looks sharp.
I certainly expect Moto GP 18 to be a step up graphics wise from previous versions and they seem to have gone the extra mile to get the tracks drone scanned at 1:1 to make them as realistic as possible and with the added finesse U4 can offer, I expect them to look really good.
The main unanswered question for me is the game physics. Milestone are talking a good game about the changes being made to all areas of the gameplay but I guess the proof will be in the pudding and the eating of said pudding.