I agree with OP. The water situation might or might not have needed some improvement but this doesn't seem to be it. Dying of thirst while standing in a lake in a rainstorm shouldn't be possible but with A21 it is. Maybe TFP's priority shouldn't have been "we must remove glass jars and let's go from there" but "what can we do to improve the water situation while simulaneously increasing immersion?" Or at least not taking away from it.
Instead what we got was the above mentioned nonsense plus the need to find a cooking pot ASAP - which should be possible just by going into the very first house you encounter but isn't. Understandably so because that would make things too easy, only this too comes at the price of a loss of immersion. A believable world, my tuchus, apparently.
And the weird thing is, it wasn't even such a hard task to accomplish, e.g. right-click on any body of water and you get a bottle of murky water, with a high chance for dysentery. Cook it to make it drinkable but still with a chance for dysentery, ditto for any related food items. Find a recipe to make it pure drinking water with zero chance for disentery.
Also, 95% of houses have a cooking pot in them because people have cooking pots. They might not have AK 47s but they have cooking pots.
edit: I just noticed, as a side benefit the three stages of water I mentioned could have finally made that iron stomach perk useful, or whatever it's called. You might want to invest into it when for a good long time in the game you don't have access to pure drinking water.