Water changes depend on your tank size and how many fish you're keeping. It's different for everyone. I will tell you that with discus, the more water you change, the better. Also, as someone else stated, you're feeding juvenile fish a lot of food, which is one of the reasons you need more water changes.
Juvenile discus are no more fragile than any other cichlid if you buy healthy stock from a reputable breeder. Keep the water warm (84 - 86F for young fish, you can bump it back down to 82 - 84F once they're older), feed them a variety of good quality foods, and keep up with the water changes. It's all you really need. I raise all my discus out in a bare-bottom 55 gallon tank with sponge filters and an AquaClear 110. I squeeze the sponges out maybe once a month in a bucket of tank water just to clean the gunk out of them. You'll also need to wipe the inside glass once a week or so because discus produce a lot of slime coat and it ends up on everything. I do a 50 - 75% daily water change on young discus. Refilling is done straight from the tap -- I add some dechlorinator to the tank and fill. You have to make sure the new water is the same temperature and pH as the tank water. If your pH swings drastically one way or the other after it has aged (because of CO2 off-gassing and whatnot), you'd obviously need to age the water in a barrel or something first. Otherwise you'll stress out your fish.
Discus are easily stunted if they don't get proper care as young fish. It's true that large eyes are a sign of a stunted fish. This is why I mentioned getting stock from a reputable breeder. Most LFS discus will already be in questionable shape when you get them. This doesn't apply to all LFS, as I'm sure some have nice stock, but I've personally never seen a healthy discus for sale locally.
Once the fish have reached sub-adult stage, around 5", you can cut back on the feedings and heavy water changes. If you have an adequately sized tank with good filtration, you could probably get away with one large water change a week for adults, which is what I do for most of my other cichlids anyway.
They're a bit more maintenance, but I wouldn't call them fragile or difficult. It's just knowing what they need and providing it to them. The tank-bred strains don't require soft, acidic water like the books all state. There's no need for RO units or messing with your water chemistry unless you're planning to breed the fish. Discus eggs tend to not hatch in hard water.
I think a lot of the myths that surround discus come from people who bought low-quality, sickly LFS stock and had problems from the beginning. If you don't start with a healthy fish, you're pretty much doomed right out of the gate. Also, a lot of people don't understand what a discus requires and they attempt to keep them as they would an angelfish or a severum. The fish get stressed or sick because the conditions aren't ideal and people write them off as fussy or difficult.