Well the tiny originals were from a different age - 32mm? 34mm? - even the later 'Jumbo' was only 40mm. The big bezel design makes them all look even smaller. The original ones are pieces of a size that few average-sized blokes these days could carry off without looking a bit silly.
IMO the Genta-inspired design only came into its own in the 00s with the 42mm models and later. The 40mm may be an attempt at matching this moment's fashion but I believe it's a mistake. If the old ones weren't selling it was probably because too many naff intrusions from motorsport had got in to the designs over time.
Thankfully not all manufacturers are falling into the trap of miniaturising their watches. Some retreat from the previous 44mm and over trend of the last couple of decades was probably inevitable and it's true larger watches can be unweildy on some wrists, but I honestly believe the market for small watches as main pieces will be limited and it won't be too long till most are back in that 41-44mm sweet spot (with mid-size available for people who need that). People are simply larger in all dimensions today, while with technology everywhere, a watch is no longer a necessity but a statement, and few want that statement to be so small it gets lost on the wrist.
Anyway it appears Blancpain have avoided the temptation to go too small with this classic design. Good for them.