Hmmm...Alright....I lay claim to 1e. I update mechanics to more modern/streamlined mechanics (ascending AC, simple/ability-dependent saves, non-combat skills as part of character creation, skill-roll tracking for rangers, et al) and expanded things from the 1e Unearthed Arcana (adding cantrips for spellcasters, weapon specialization, etc...). And throw in a subsystem of ethos/reputation/infamy points (or somesuch) to make alignment a real, in game, serious thing.
The class list is somewhat expanded and modified to include the Barbarian, Acrobat, and Cavalier from 1e's UA, make Bard a base class that doesn't require separate fighter and thief and druid levels (i.e., you can just me a 1st level Bard at 1st level), and add a couple -whether subclasses or their own- to fill in multi-class options (esp. Ftr/MU, Thf/MU, and MU/Cle) that could be their own classes. So, the class list looks different. The player race/species list, on the other hand, involves a bit curtailing. No more 8 kinds of elves. No more "deep/underdark" species.
I would also go "high fantasy." I would go real "heroic" (be the good guys in a "good vs. evil" world) focus. New setting development. New, full, pantheon of setting deities (the choice of whom is built in to the "divine" class creation/development).
PRODUCT #1: The Advanced Dungeons & Dragons Creative Compleat Starter Box Set: Player's Guide, DM's Primer, Monster/Lair Book, new setting starter adventure module (incl starter village and dungeon maps), Empty dungeon map sheets (3), Dice (6).
PRODUCT #2: The Netflix (or Prime or Hulu, I'm not picky) AD&DCC Animated Series featuring a cast of alluring and interesting diverse classes and species of characters (perhaps some rotation, episode to episode). Geared towards teens and adults as far as content. More Critical Role/Game of Thrones (characters do/can die! Romantic pairings/plots and sexual situations - across the spectrum - are possible. Language and mature themes, for sure). No Saturday Morning cartoon, this.
PRODUCT #3: (really a "2a," since these should release as close together as possible) Action Figure adventure line, featuring multple male and female characters of various species and classes. "Iconic" characters that will be used/appear in #2.
--3a: game-sized/scale mini's of same.
PRODUCT #4: The Monsters & Lairs Manual (a fully fleshed out monster book that includes some specific mini-adventure "lairs" that may also include/introduce a few new treasures/magic weapons/items)
PRODUCT #5: The Setting Set: full box of new setting material, incl. giant color world (or at least starter region) map. Maybe includes some new setting specific classes., species sub-cultures, and expanded treasures and magic items.
Done. Million dollars. Done.
[RE-EDIT cuz I forgot Ranger!] So the class list is looking like...
Cleric
--Druid (nature magic guardian/champion)
--Paladin (heavy armor, divine magic guardian/champion)
--Theurge (light armor, multi-magic guardian/champion, Cle/MU multiclass option)
Fighter
--Barbarian
--Cavalier (non-magic knight)
--Monk
--Ranger
Mage (nee Magic-User)
--Illusionist
--Seer (Psionic/psychic powers "caster" class)
--Swordmage/whatever name (Ftr/MU multiclass class)
Thief
--Acrobat
--Assassin
--Bard (Thf/MU - yes with illusion and druid spells too- multiclass class)
[/EDIT]