I think an ocean size of 1.6 should still happen in 1.7, but only be extremely rare. As in once or twice per seed.
But on the other hand, these are highly zoomed out pictures. Jeb says that several of those oceans in the 1.7 view are some 3k blocks large. So perhaps it won't be that bad at all.
On a side note, I hope they turn down the number of generated ponds- there's too many of them.
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