If youve plateaued with what youre doing, I would incorporate a DC-training style leg protocol.
Calves include a single 12 rep set, with 5 second negatives and a 5 second stretch at the bottom.
Hams generally get a 12-20 rep set.
Quads get 1 set of 4-6 reps, followed by a set of 20 reps of the same exercise with a slightly lighter weight.
Alternate between 3 exercises for each part, and increase weight and/or reps each workout. If you are eating correctly, getting adequate rest, and progressing with the weight your legs will grow.