Hussar said:
Now this I find interesting. Outside of chargen, what could a player really do to invest his time in a DM's campaign in earlier editions? Any plans or ideas he may have would have to be vetted by the DM and could be vetoed pretty quickly by in game events. The player couldn't spend time thinking about equipment (completely the purview of the DM), hirelings or henchmen (again, DM), proficiencies weren't exactly time demanding, spells (DM, again). So, what could a player do with his time to add to his character outside of game time?
"No plan survives contact with the enemy." --Murphy's Rules of Combat
That things might not go as planned is not a reason to not plan. The considering of all the things you list happens without the DM present. Only the "vetting" itself requires the DM.
Unless the player or the DM are complete jerks or seriously mismatched in their approach to the game (with no effort to reconcile that), not every player idea is going to get outright veto'd. Rather (IME) little will, though the results might not be exactly what you expect, but that's part of the point of playing the game with other people, right?
If it is an issue of jerkitude or mismatched approaches, then you've got a much bigger problem than how involved the players can be.
Some players put just as much effort into their PC's backstory, personality, &c. as DMs put into their campaign settings. & many DMs will welcome their world being partially shaped by the players. Sometimes as far as letting them develop portions of the setting.
Of course, there's also the argument that the DM's job was easier, so that lowers the bar for players being as involved as the DM. (^_^)
Take the idea that 1e is humanocentric. This honestly never occured to me. The groups that I played in played mostly demi-humans. I was odd man out for playing humans usually.
I wanted 1e to be humanocentric & was always annoyed that it wasn't. I can enjoy a game that isn't, but I don't want that all the time.
This is one of the things that I really enjoy about Moldvay/Cook/Marsh D&D. As written, the limited range of non-human PC choices & their increased XP cost tends towards more human PCs but still with the occasional demihuman. & I have plenty of resources (from oD&D through the Gazs & Crucibles plus pretty good fan-made class creation rules) to make doing things different pretty easy when I want to.
(Although, for the "any race goes" kind of things, I think I'd prefer Gurps, Hero, Risus, or something else to anything D&D.)