I assume you mean you will say you can have a choice out of these classes and these races the setting is like this what character would you like to play and then go, here read the PHB, the applicable sections only for your character and then the rules sections.
Its a neat idea and one that in all likelihood can only be done at the start of a new system, it helps accentuate a roleplaying esque type game by letting players focus on their character rather than the stats (a suggestion I am all in favour of) In my opinion a knowledge of the rules will encourage certain combintaions whether its min-maxing (a dirty word/phrase) or the opposite which will influence character concepts.
No one can win D&D (I feel that the word Game in RPG is some what of a misnomer as it suggests winning) so whats the point in making your character the best, by encouraging power gaming (not saying that viewing the PHB before hand especially encourages this) you are, as you put it "well done you've taken some of the r out or rpg."