I agree on all these.
Languages are one of those niche areas of any RPG which a gaming group could choose anything between totally ignore the topic and make it a strategic resource. Similar cases can be said for encumbrance, spell components, rations/water/survival and more.
On a very high level, I think D&D designers always lacked a more ambitious vision for the game to be a giant toolbox that each gaming group can setup according to their playstyle preferences, instead they always choose a lukewarm middle-ground default: languages are in the game but not too much, encumbrance is in the game but not too much, and so on... just not to alienate players who hate one extreme or the other, but then the DM still has to do some work to decide how much to handle the topic without any support from the books. So there is a default set by the books, but the default is lousy and not sufficient for the DM to count on it without additional work. Why not providing at least guidance for the DM on how to dial?
Negating spells are always part of the problem. They exist exactly to make an entire (potentially interesting) topic irrelevant, if it annoys someone. Managing light sources such as torches/lamps as limited resources, keeping track of their ranges and duration, is potentially a very interesting strategic element of a RPG for those who want it, but at the same time it can be totally a dealbreaker for another gaming group who has zero interest in this strategic element. So what do game desigers do? They put it in the game, but then they also put "switch off" abilities (low-level light spells) that entitle players to remove the strategic element entirely. Perhaps the crux of the matter is that they put this into the players' hands instead of the DM, which means that according to the rules, a single player who doesn't like the strategic element can remove it from the game for everyone, unless the DM intervenes but then becomes adversarial to that single player.
If they haven't learned a better way in 50 years, I have little faith they ever will.