From what I understand theoretical improvements in factoring algorithms go hand in hand with theoretical improvements in discrete logarithm algorithms, and for both there are algorithms which improve slightly over the trivial approach. ECC is considered better because of the believed constant factor slowdown in arithmetic operations on elliptic curves, not because discrete logarithm is considered harder than factoring. This article implies the opposite quite directly.
You're not quite right. The hardness of the discrete logarithm depends a lot on what mathematical structure you are using below.
For example, the discrete logarithm on the group of the integers modulo some prime is known to be more or less as hard as breaking an RSA modulus of the same size. Those are the two problems that seem to be linked together.
However, attacking the discrete logarithm on the group of points on some good elliptic curve is a very different problem, and the same techniques that work above just don't seem to apply here. So you're stuck with the generic attacks, which are much slower.
Bottom line: the discrete logarithm on elliptic curves is harder than factoring and the discrete log on the integers modulo a prime.
