This debate is confusing the heck out of me.
I like the idea of doling out your opening powers over three levels. A wizard learns the basics before being asked to pick a tradition (how very Tower of High Sorcery), a fighter masters some basics before declaring what focus he will use for the rest of his days (nothings worse than spending your first feats on two-weapon fighting, weapon finesse, and combat expertise and then getting a +1 greatsword as your first magic item).
For a new player, its training wheels. For a more experienced player, it gives him two levels to feel out his character (and see if he lives) before deciding on what paths he will go in further customization. Right around the time PCs are getting 2nd level magic and their 2nd feat, they should start looking at what paths they want to choose. THAT'S when fighters, rogues, and wizards should become Slayers, Acrobats, and Necromancers!
As an aside: I am adamantly opposed to 0 level levels. Why not just make the bottom level 1 and quit adding basements. Reminds me of a famous movie quote: "Why not just make 10 louder and make be the top and make that a little louder?" "These goes to 11!"
If you want that famous "4e feeling" of high hp and accomplished heroes out the gate, start higher and forget the apprentice tier. If you like the feeling of farm-fresh orphans getting killed in kobold mines, start at 1. And its not like there won't be ANY customization: feats/archetypes and skills/backgrounds will still be there. Its just the classes won't break out all their toys for those "one level dips" anymore.
Honestly, the only complaints I can see is from people who want their heroes uber-kewlz out the gate and don't want to wait 2-3 sessions to play with all their toys.
