Okay, I can understand why they would lose cars like the (very boring)Citroën C1, but there are other cars in F (and E) class that really do have something to offer, even if they are slow.
Another thing... From what little we do know we've learned that you'll be able to change the look of your cars in Horizon. Now, if you look at the latest DLC cars in FM4 (incl the Porsche pack), they all have a lot more body options than before. Would they really have put all the extra effort into these car models if they were only going to use them in FM4?
So I'm still hoping we can expect E & F class cars in Horizon. Just look at all the bodykit options you have for the old VW Beetle that's been launched today!