honestly no it does not speak well of the system, it shows a lack of faith in the design of the game and intelligence of the players in Al
sure sometimes something gets made in a game that does not play well with something else, but when you spread out player info but limit its inclusion, thats a negative IMHO.
now wizard seems to be trying to fix this to a degree with xanths guide but is having to waste space with stuff from sword coast due to the limitations introduced by book +1
this will only grow worse as the game ages, lets assume the crazy possibility that wotc releases a new player book next year, then what.
will xanths 2 have to duplicate important spells invocations etc from xanth 1?
if your running in a forgotten realms setting are we goign to exclude faerun races if we want to play with xanth book 1 or 2?
that makes book + 1 the game more complex then just including non banned stuff.