I don't like people supporting the notion that perks can cover for some of the more obscure things like encumbrance. Good luck trying to fit a carry weight perk into one of the current skills and then trying to explain it. I do share your concern here. Perks can do it, but it's going to be so awkward and the gains are going to be incredibly sudden. Far less gradual than when the game used attributes.
"After bracing against so many attacks, the Dovahkiin's shoulder muscles used for holding shields have notably strengthened themselves, and now he can carry more things on his back without chafing and bad posture problems. INSTANT +100 MAX ENCUMBRANCE FOR BLOCKING AN ARBITRARY NUMBER OF TIMES!"
There are also "Racial" and "General" perks in addition to the skill perks, aren't there?
Or, encumberance could make sense as a Heavy Armor perk: Since heavy armor is so, well,
heavy, it would be appealing to those characters to be able to carry more, so they can carry backup suits of armor, or just be able to compensate for their reduced carry capacity from the extra weight. And, since Move speed and Jump height likely figure the ratio of Current to Max encumbrance in performance (As they have in the past), it also allows a heavier-armored character to become slightly more mobile in the extra weight.