Of the 4 parks... DAK is in the lest need of a major expansion right now.
-MK needs high capacity NEW family rides, just look at the waits for the 7 year old seven dwarfs.
-EPCOT is currently getting it's big update... but will it be enough. They need some more top tier rides of which they will only have 2 (TT and GoTGCR). EPCOT needs it's 3rd heavy hitter and I'm not sure RAT is enough, Frozen and Soarin just don't cut it compared to the other parks.
-DHS is incredibility top heavy with 4 E tickets (ToT, RnRC, MMRR, RotR), 3 Eish/Dish tickets (SDD, TSMM, MFSR), and only 1 C ticket (Alien). DHS needs it's Fantasyland with 3-4 B and C ticket rides. The park is underbuilt with only 7 Rides
AK has the best balance of the non MK parks. 3 E tickets (FoP, EE, KS), 2 solid D tickets (KRR, Dinosaur), and 3 C/D tickets (PW, TriSpin, NRJ). Couple that with animal walking trails and the best 2 stage shows on property (fight me).