So basically also a list of different things you should have or be able to fight against at any given level should be included? Or at least a rough guideline, since there is no real consensus about most of those things.
Yeah, kinda. I often go to the MM and pick out a bruiser of roughly the right CR and check his AC, to hits, etc. and see how I stack up.
I think it's good to just list the conventional wisdom on a lot of things, which itself should only be a few pages, w/ the proviso that ymmv depending on the level of optimization present in a given campaign. For example, I played a high level direct damage sorc and had a ball in a recent campaign, but we were being relatively restrained and he was a pretty optimized blaster.
Actually, w/ the possible exception of some terminology or basic game concepts (action economy, etc.), and maybe some very fundamental ideas (the problem w/ monks is that they have no synergy between their class abilities, emphasis on role v. class, etc.) I think just exemplars of various archetypal builds could go a long way. Something like, "this is what a really solid basic blaster, tripper, power attacker looks like, and here's why ..." Although perhaps those who actually intend on using this handbook would prefer a different approach.