Yes, Ledecky is amazing. Starting out early, in clubs, the 1500 is the shaft race that nobody wants to do. The person with the most heart is assigned to race it.
When it gets more serious, the competition in the 1500 really is not as good as it is in the shorter events--however, that doesn't diminish Ledecky's greatness at all, considering what she has done.
There is that 800 split in the 1500 race, then there is her ability to win at 400-up. At 2013 FINA world's, she won the 400, 800, and 1500 free, and was part of the gold medal 800 free relay.
BTW the 800 was a WR, the 400 an AR and second-fastest time ever behind Pellegrini's techsuit WR, and the 1500 a WR. For you nonswimmers, that is unbelievable.
Yes the distance stroke is different than the sprint stroke, but she has proved herself over 200m in relays. If the schedule allowed, there is little doubt that she could be at or near the top of the 200 world as well. That is phenomenal range. It's like having WR's in the 5k, 10k, and marathon, and being fast enough at 400 to be on the world gold medal 4x4 relay. Are you kidding me? The only thing she would get beaten at handily would be the 100 and 50, which are sprint territory.
She is better at swimming than Cain, et al will EVER be at running, relative to the competition, both current and historic.
Again, her WR's were done without the speedsuit.