It would be fairly easy to re-introduce the concept of mantles to 4e. A mantle would simply be a collection of powers of every level related to the theme of the mantle: one 1st-level at-will power, encounter powers of 1st, 3rd, 7th, 13th, 17th, 23rd and 27th level, daily powers of 1st, 5th, 9th, 15th, 19th, 25th and 29th level, and utility powers of 2nd, 6th, 10th, 16th and 22nd level. A 1st-level ardent selects two mantles, which give him both his at-will powers, and then selects his encounter and daily powers from the mantles he has picked. Humans might have the ability to select an at-will power (but only the at-will power) from a third mantle.