If not, you should add front squats as an accesory to back squats and do them in higher reps. After that, go to the leg press and place your feet on the plat form high woth wide stance to hit the hams.
You should also consider moveing the extensions and curls to the beginning of your work out ...
Muscle in Korea: It would just add further work for quads, whereas you'd only do 3 sets for hamstrings. I believe that the hammies would love more work, some type of deadlift, which can be done both for low and high reps. Then leg curls for high reps.
Strong and big hammies are paramount for anyone I'd say. Most people tend to do plenty of work for their quads, but neglect those mucles in the back of their thighs.
Heck, I do variety of hamstring curls, I love them seated, lying, standing, for high reps, low reps, I love stiff legged deads, romanian deads with barbell, dumbell, smith maschine.. Don't neglect those, try different ways for punishing them!
In terms of hypertrophy - no. A lot of people make this mistake, even seasoned trainers, but no they do not get enough stimulation to cause growth. Many think the soreness they get in the adds and or hips are HS DOMS, but it is not . Unless you have unbelievably horrible form, which I do regularly see, and are virtually doing goodmornings, you will not adequately stimulate the hamstrings. I have never gotten DOMS in HS from doing squats (not that this is the marker for HT). You will get EMG activity in the HS, you will even get EMG activity in the calves, but would you rely on squats to build up your calves?
I would rotate FT and BS eack workout, and not do them in the same workout. It is too similar of a movement IMO to do in the same workout in terms of optimal placement. I personally don't like that workout, it's not bad, but I would try something more like the following.
Squats(alternate front and back each workout) 5 x 12, 8, 6, 5, 5 Leg Press 4 x 12, 10, 8, 6 Walking Lunges 3 x 15, 12, 10, 8 Stiff Legged Deads 4 x 12, 10, 10, 8 Leg Curls 4 x 15, 12, 10, 10
FS/BS are fine, though you're going to want to work up to weight in FS. I do FS as part of my warm-ups, don't consider them a key lift. I'm about 100# below my BS weight for FS (~225# vs. ~235# or so).
I'm not a huge fan of leg press, but I do some heavy high-rep work on the sled (15+ reps). Sissy squats will also work quads. Extensions and curls can be hard on knees, I'm not a fan.
What are your weak points in your squat? Hole? Lock-out? Mid-range? Depending on these, focus your training.
Box squats, hip/glute thrusts, and step-ups are other areas you can work. Step-ups will work glutes and hip extension while not overloading your back, they're also good for balance and balanced development.
I also like to do chins of some sort with squats just for spinal decompression.