Ulmo make a giant tidal wave?
Yeah, kill all of the Elves in Alqualonde and Tol Eressea and any settlements on the coast of Middle-Earth. I'm sure the Valar would support that plan.
Plus, I'm not sure how easy it was to do something like that, let alone do lots of them one right after the other. And make no mistake, it would've taken some really nasty waves to take care of the greatest mariners the world has ever seen. Lots of waves. Very big ones. And miles and miles of them.
What I'm saying is, I don't think it would've been easy at all to overcome the Numenoreans. I don't think Ar Phar and his lads would've killed any of the Valar or anything like that (because the Valar never shackled themselves to their bodies like Morgoth in his effort to gain greater power), but I do think they could've broken pretty much everything breakable and killed pretty much everything killable before they were stopped. All in all, I'm saying that we should not take lightly or dismiss the greatest force of war ever in Middle Earth.
I like that letters quote,
Ibrin. The business of Ainu imposing their will upon the Children of Eru pops up again and again. Saruman versus Gandalf, right?
And wow, your name is long.