I am not aware of all your posts by a long shot. Maybe I have come across you suggestion for this, but I don't remember it. Do care to elaborate?
Simply saying Novice levels and incremental advance(ment?) rules does really mean anything. I mean 5e has novice levels* and incremental advancement, but we know that doesn't work for you. So, what do mean and do you really believe one solution will work for all?
*I have seen people say 5e has to many novice levels and some say it has not enough. Not sure how to bridge that divide.
5e does not have novice levels. It has two regular levels which have been saddled with needing to serve three different masters (OSR players who want a brutal, low-competence, minimalist experience; brand-new players who don't know what they're doing and need a gentle introduction; and simulationist players who want to grow naturalistically).
Actual "novice level" rules would be, effectively, levels "between" nothing at all and a 1st-level character. So, for instance, maybe you have at rock bottom 8's in all stats, 1 hit point (and no hit dice), zero proficiencies, no background, no species, no feats,
nothing else. Obviously I haven't tested this in any way, so please don't rip it apart by mechanical analysis; the point is simply to illustrate, not to prescribe a specific fixed solution.
Novice levels would thus provide a structured framework for building up from this absolute rock-bottom minimal character, slowly filling in until, eventually, you build up to finally being an actual 1st level character. "Structured", however, does not mean "perfectly dot-by-dot spelled out with zero deviation". Novice level rules, if well-structured, could very easily be bent in multiple directions:
- OSR-style, you start out with pretty much just the above. Maybe everyone starts out with the Human species package, but otherwise completely blank. Gain (say) 200 experience, and you get one "novice level"--meaning, you pick up one single additional piece. Maybe you assign your Strength a high score for that level. Another 200 XP, you learn you have magic--perhaps divine magic, setting you on a course toward a melee caster like Paladin or Druid. By spooling these bits out slowly over a long period of time, a character might take six months before they finally have reached "first level" and thus start moving forward by regular level rules (but see below re: incremental advancement).
- Tutorial Adventure mode. WotC could use these rules to make those "choose your own adventure"-style structured hooks into an actual, "learn to play" process, which can then let players explore their choices before locking into something. So maybe you start out with 1st-level-character HP and HD (presumably d8, since that's pretty much "average" HP now), but no species and no other features, 10s in all stats. Present it as an amnesiac recovering their memory, trying skills to see if they can, that sort of thing. If monster-design stuff is made compatible with the system for novice-level rules, you can even have combat and real challenge, all while still being focused on building up the skills through play, rather than merely through being talked at by your DM or reading lines on a page.
- Traveller-like character creation. A character creation method you play through, rather than one you just crunch through before you can start playing proper. Character naturally builds up to a set of skills, and then the closest-fitting class is chosen once you've hit a critical mass and reached 1st level. Allows for players to express themselves and to explore the natural growth of a character responding to their environment, rather than having to artificially declare all this stuff about who they were and where they went and what they did etc., etc. that many simulationist fans dislike so strongly.
Under this paradigm, a 1st level character does in fact have a little experience under their belt. They might still be green, but they aren't
completely untested. That's what novice levels are intended to capture. So you would be choosing things like your "subclass" (if we preserve such things) at 1st level, and folks who desire to build up to that would instead start somewhere in the novice level rules.
"Incremental advancement" is a similar but distinct thing, taken directly from 13th Age (a game that has many very very good design ideas). TL;DR: Instead of gaining a full
level, you can pick just one benefit to enjoy
as if you were a higher level--and you can do this repeatedly, getting just a little morsel here, a little morsel there. In 5e terms, let's use a Sorcerer as a pretty good example. So, maybe for your first incremental advance, you pick up a Sorcery point (since those are normally keyed to your level, once you get the feature). Second advance, you pick up another spell known. Third, maybe you're about to hit level 4 so you pick up a feat or ability score increases. Or maybe you increase your proficiency score 'cause you'll get that bonus at your next level. Etc.
By having incremental advance rules, DMs can choose to spool out the levelling process almost as long as they like, while still giving their players tangible, obvious
progression. Characters aren't stuck, utterly unchanged for 5 months and then suddenly getting a spurt of growth: instead, they slowly
creep up to that, getting a bennie here, a bennie there until finally they cross the threshold.
Between the two, it is (at least in principle) entirely possible to construct a game, including reasonable threats and well-built encounter-design methods, which actively supports
both the brutally-hard, outright-zero-to-hero, slow-methodical-growth experience that OSR fans love,
and the baseline-competence, adventurer-to-legend, snappy-progress experience that contemporary fans love, without either side being treated as lesser or deprecated or inferior. Indeed, both sides can even get into
dialogue with each other, possibly sharing some of the good side of their experience with the other, who might not otherwise have considered it.
Given these rules need to be treated with equal respect as any other approach to play, they obviously need to be put front-and-center, and their usage needs to be truly
supported, meaning, they aren't just a fire-and-forget, they get ongoing attention and new content over time. I am quite serious when I say that, if I were in charge of developing 6e, making sure players who use these rules
never feel sidelined would be a top priority, even though I personally have negative interest in ever using these rules myself.