I'm worried that the OP may be doomed to a great deal of disappointment with D&D in general, because no edition of D&D has ever supported Bildungsroman as part of the default setup. (Some attempts at level 0 have come close, but since that may still exist in 4E for all we know, it is not relevant to the discussion, which has up until now been specifically aimed at use of first level characters.)
A first level fighter is not a farmer stepping off the farm for the first time. He is proficient and trained in almost every single weapon and armour type known to man with the exception of a few, mostly oddball weapons that most soldiers would never touch. He can go toe-to-toe with critters that kill the peasants around him, and slaughter them in one blow, or in some cases more than one with a single blow!
A first level wizard has completed their apprenticeship, and is ready to set out into the great wide world to make a name for themselves. They have gone past the cantrips they struggled to master while they were mere apprentices, and have learned actual spells, spells capable of killing a man in one cast (magic missile), or killing a roomful of peasants (burning hands). No wizard in his right mind teaches that sort of spell to a raw apprentice.
A first level rogue is no raw orphan learning to pickpocket - he has mastered the basics of a variety of skills and has even learned where to strike a target for maximum, lethal effect. That's no rank amateur.
And first level clerics have progressed far enough in their training and faith that when they call upon their god for aid, they get a bona-fide act of divine intervention, even if it is just healing a wound! How many peasants can do that?
All of them have one thing in common - they have progressed past the need for an active and protective mentor. They even have starting equipment far beyond what any peasant might be expected to possess, so not only are they trained, they're also adequately equipped.
D&D is not, and never has been, a game where first level characters are the untrained everyday farmer/scullion/orphan central to the Bildungsroman genre. They are the militia member, the skillful pickpocket, the fresh graduate from the temple or the academy. They are already past the need for a full-time mentor, and have reached the point where they need real-world experience to hone their abilities and broaden their repertoire of abilities.
Yes, their power level is low compared to many of the threats they will need to rise to meet, and they may be near the bottom of the food chain for now, but they are no longer everymen.
So 4E will need level 0 rules to even come close to a Bildungsroman. If they don't exist, then house rules will be required, since third party supplements are forbidden from including rules that explain how to level up characters.
