When I'm not playing a wizard or a sorcerer (a wizard with extra slots, scant choice and very little knowledge), I like to go to the other extreme. My second favorite class is barbarian. Now from a rules prospective a barbarian is a tough fighter who gives up specialization and metal armor for swiftness and rage (sweet). In fact, as much as I loved the class in 1st edition, it really was no surprise it did not make the cut in the 2nd edition PHB. Of course, barbarian (and ninja?) would later return in AD&D 2nd ed. "kit books". And to be honest that is probably where they belong. The way D&D Next character generation is setup, all the stuff that makes barbarians different from standard "civilized" fighters could be put into a background and a set of feats in a speciality. I doubt many other gamers find that shocking, but when I suggest that, most, if not all of the non-core classes could probably be justly done this way, that might raise a brow or two.
But in truth ranger, paladian, shaman, monk, and druid are specialized (or hybridized) versions of a core class. I think if we list fewer classes and make multi-classing more appealing, then this type of "class building" could be really cool. But one thing that stands in the way ( in my view) is serious front-loading of feat like abilities. For example, if we are going to make barbarian a build that starts as a first level fighter then every 1st level fighter cannot already be proficient with heavy armor.
Now I understand that WotC did some research before publishing 4th edition and found that most players don't like 1st and 2nd level characters, and that the 30 levels of play in 4th ed. were meant to be on the power level of like 5th through maybe 20th level of 3rd edition. In spirit I get what you were doing, and it seems that D&D Next (at least the first playtest) starts characters out with a little power bump as well. Actually from 3rd edition on 1st level characters have had considerably more power than in AD&D; measuring by skills, proficencies, and feats(which were new).
But what about the players that like the idea that a 1st level character has had NO adventures yet? How is a fighter that cannot afford breastplate already proficient with full plate? How can a wizard that can barely cast 1st level spells already write scrolls? It seems to me that it would be easier on the players if WotC would design the level progression in such a way that groups who want to start the game as village teens who've just picked up weapons and wands can do that by starting at 1st level (or maybe even level zero for the truly hardcore); then groups who want to play somewhat experienced adventures could just roll up 3rd or 5th level characters. It is easy to skip a few levels, especially for experienced players, but if the game is setup so that 1st level is already "seasoned" it is far harder for players to extrapolate below the preset minimum.
Well when I sat down tonight I was not planning on going into more "rules talk". I sort of had it in my head to type about the barbarian being a fun way to keep the game moving. Then I remembered the AD&D "kits" and got side tracked. Oh well, so this has been a side trek on buildable "mini-classes" and the need for a lower minimum power level. Like I always say, "just brain-storming".