I agree on the Saddle bag - it looks so 2005 and I never like the shape of it either. Especially in the Oblique canvas it's just not so appealing.To me, the Dior book tote may look dated in a year or two. The Dior saddle bag, personally, I just don't like the shape of it. Others may love it though.
The Book tote - I think you can get similar bags for less than 100€ that will wear better. I really like the shape of the Book tote (wide bottom = more space!) and found a great alternative in Coach Field tote which I purchased in the size 40. It's in coated canvas so it will last an eternity. It cost me more than 100€ but I'm thinking it was still very much worth it at 375€.