If the ring HAD gone over the sea, the good peoples of middle earth would probably have been destroyed. First, there would have been no Fellowship. Therefore, Aragorn would not have gone south, to gather the Oathbreakers. Minas Tirith would have fallen to the Witch King and the Corsairs. Gandalf would not have died, therefore no Gandalf the White to help Erkenbrand reinforce Helm's Deep.
And I do not know of any evidence. Sauron did not have any bases on the shores of Eriador; that is why he did not consider hobbits. Interesting thread!
