toucanbuzz
No rule is inviolate
And I get that armour is heavy, but that puts plate+shield+sword at 15 slots. Not even the strongest human is going to be able to carry a 6-slot pack on top without being encumbered. RaW might be too generous, but this might be pushing things a bit too far in the other way IMO.
The RAW variant is STR x5 pounds before becoming encumbered. With Plate (65) + Shield (10) + Long Sword (3), we're at 78 pounds. A 16 Strength character can bear 2 more pounds of anything before becoming encumbered. Add a backpack and you're down -10 speed. In prior editions, heavy armor automatically slowed you to 20 speed. So the RAW aren't being changed and the designers actually kept it in line with precedent. However, unlike prior editions, if the heavy armor wearer can lighten the load, they can move normally. (I linked in another reply an article of someone spending his day in heavy armor, and there's a youtube video out there of something testing whether you can swim in breastplate armor, answer is yes).
That's been a source of debate as far as whether rations should weigh 1 or 2 lbs. A ration supplies 1 day of food (1 pound by the rules is needed), leading people to wonder WTH is the other 1 pound of those rations? Mike Mearls replied it's heavy junk food. In war, weight and speed is important, and I'm in the camp that rations, which are designed for wartime situations, would be as light as possible.Also, rations are still proportionally under-weighted. Carrying food for a week and water for a day should be heavy.