Niiiiice taaasty brrraaaaaiiinnnsss!
A few more points I thought of.
There is a lot of gold coinage used in D&D -- either there are a
lot more gold deposits in the world or there is some form of "bankers notes" passed around a lot. In any case, D&D is far more mercantile than the Middle Ages. I would think banking would be a far more important and widespread profession than normally seen in the game.
On Magic: Will all magic be used positively? No. Will destructive magics be used every single day in every single town? Nope. My feeling is that the non-destructive magics would actually be far more common and that most magi would work with these, many not as Grand Adventurers, but as Small Magics for Hire. Then again, given the base spell list, the lie might be put to this, as most spells, by a long shot, are combat oriented. I have to wonder if this isn't just the "Adventurer's List" of spells, if there are not a long list of "less useful" spells that most wizards and sorcerers use on a daily basis. But even at that, consider the many social uses for Flare, Light, Ghost Sound, Mending, Open/Close, Prestidigitation, Alarm, Hold Portal, Grease, Mount, Unseen Servant, Comprehend Languages, Charm Person, Hypnotism, Sleep, Tenser's Floating Disk, Change Self, Silent Image, Ventriloquism, Animate Rope, Enlarge, Erase, Expeditious Retreat, Feather Fall, Jump, Message, Reduce and Spider Climb (just to choose 1st and 2nd level spells) in the ordinary world. This could be insurance, small merchant, wide varieties of entertainment, shipping & recieving, messenger services, and suchlike. Almost any sizeable business would want at least 1 wizard or sorcerer on staff with the "right" combination of spells.
Good, Evil, Law & Chaos would be absolutes in such a world, not something to be guessed at (except due to repeated and powerful uses of anti-detection devices and spells). But are Evil people Evil 24/7? Probably not. Thus these terms might become much more ... mitigated, for lack of a better term. A Lawful Evil 1st level commoner is not much of a threat, to be certain.
Would there be Halfing Ghettos? Anti-Half-Orc Movements? Would You Let Your Sister Marry An Elf? Again, the social implications of this many races and half-races, especially once you start adding in all the secondary and tertiary races, becomes quite staggering.
Common. Everyone everywhere speaks one language. Wow. That, alone, is a huge implication.
More when I get my brain back