I find stuff easier to find because of ravines and mineshafts surely, however it wouldn't be a stretch if the spawn rate of resources changed in the biome rewrite. In fact in my new survival world I spawned near a ravines and got my first bits in iron and coal with barely any digging (thank you nearby lake for you water elevator). Also the first mineshaft I found had gold right there at the beginning (also a dungeon but that's unrelated).
They had to up it a bit. Otherwise you could be losing out on hundreds of iron/coal because of deeper oceans and the ravines. If consider how deep and how huge oceans are, it can be... well lots and lots of coal/iron just gone if they kept the spawn rate the same.