Okay, it seems that many of us in here don't like the direction Slimane took the bags in. So, in order to be of more help to you, let me ask you some questions -
What do you like about this bag? Was it merely the fact that it is a flap bag?
Also, why did you say "but I'm not entirely sure about the design"? What made you unsure?
Answering those questions would likely help others and yourself in determining whether this bag may be a good fit for you
Personally, I have to join the chorus with a resolute "meh" to this bag. YSL had a lovely Y Chyc flap that was lovely IMO. I'd recommend flaps from Lanvin (Madam Lanvin, Happy), Celine (the Box, the Case), Valentino (there's a lovely one Miranda Kerr has been seen with recently), Dior (Ms. Dior, I believe).
These are all lovely options, assuming you want a flap bag but not a Chanel. Many of the other options I noted will look fabulous many years from now.
This Betty bag looks like it would look great in a futuristic or '80s photoshoot. But would it work for you today and tomorrow? If your answer is yes and your wallet agrees, go for it!
Best of luck with your choice. (Sorry for the long response)