The adventure isn't "In Search of the Unknown" by any chance?
The pick-a-path character generation is an intriguing idea. I suspect the class choice will give the genuinely new player a stilted view of the game, though. If they'd stuck with the PH classes, it wouldn't matter what class you picked, you'd still be getting a clear idea of how the game worked in the most basic mechanical sense, for all classes.
Now that the classes have been differentiated down to basic mechanics... I don't know, it seems like that will make it harder on /new/ players. Returning players, OTOH, will probably want to pick options and investigate all the classes - and get little thrills from the familiarity of the 'Thief' and 'Mage' (and wonder where 'Fighting Man' went - too sexist, I guess) - which makes the pick-a-path format less than ideal.
It's pointless second-guessing at this point, but I suspect the Red Box would have been better released as an 'Anniversary Special' targetted explicitly and entirely at returning players.
A product to attrack genuinely new players would have been good, too, of course, but probably shouldn't have been released at the same time, let alone been the same product. Resources are limitted, though, and there's the potential for confusion. D&D was plenty confusing when I was a kid, there were the old sets, the Basic Set, the 'Advanced' books (that weren't actually the next step after 'basic'), and all sorts of suplements, TSR & third party, that didn't bother specifying which of the three versions of the game they were for...