The Lord of the Rings isn't a civilisation. It is a novel. A novel in which travelling over the sea is essentially a one-way ticket and otherwise forbidden by literal god-figures.
Passing over the sea, the call of the sea, the arrival of hope/doom by sea etc. are all strong recurring thematic elements in the narrative. To append a sea-faring adventure on treasure island to the IP is to reveal a complete lack of respect for the source material.
The Hobbit and the Lord of the Rings are novels set in a civilization imagined by Tolkien to provide a background for his invented languages. The Lord of the Rings game is set in this civilization, and except for the saga expansions are explicitly not set in the novels. FFG also has a right to use material from the appendices, though sadly not the Silmarillion.
The one-way ticket you refer to is only relevant to completely crossing the sea to seek the undying lands (after they were removed from the circles of the world). There is no prohibition at all against traveling by boat in the sea, and we know from the text that the Corsairs (i.e. Pirates) of Umbar did so. We also know from the Council of Elrond that after Elrond said they could not send the ring over the sea (i.e. on a one way trip), Glorfindel counseled to "cast it into the deeps", Gandalf responded that "There are many things in the deep waters; and seas and lands may change." Both Galdor and Elrond add that Sauron would expect them to go that way -- clearly, a sailing to trip to "the deeps" was plausible.
Moving to the appendices we know that both elves and men sailed east as well as west before the fall of Numenor, and that the Numenoreans were particularly notable for their sea power. But even after the fall, the Corsairs were not the only ones to sail on the sea. Cirdan attempted to rescue Arvedui by ship, and in the shipwreck that followed he wrote "even the mariners of Cirdan were helpless", implying that the mariners were highly skilled, impossible if their sailing was confined to one-way trips overseas. The kingdom of Gondor was also naval-minded, Tarannon was the first of the ship kings who built navies, Earnil I built a great navy and took Umbar, which withstood a seige of many years "because of the sea-power of Gondor", and at Gondor's peak strength they ruled the coast all the way to Umbar, with the kings of Harad doing homage. In the civil war Castamir took the fleets and established the Corsairs of Umbar, but we know that the Corsairs were not the only one that subsequently sailed, because from then until Aragorn's time they were "a threat to its coastlands and all traffic on the sea", an odd description indeed if traffic on the sea was forbidden by the Valar and not practiced except for one-way elven trips.
In Telumehtar's time Gondor acquired sufficient naval strength to storm Umbar and kill Castamir's descendants, though it was soon lost again during the wainrider crisis. Against the witch-king, Gondor's army was sent north under Earnur with a mighty fleet, "so great in draught and many were his ships that they could scarcely find harbourage, though both the Harlond and the Forlond also were filled."
Between the Hobbit and the LOTR (i.e. the very time period of the game), Thorongil [Aragorn] was "a great leader of men, by land or by sea". His final action for Gondor was a raid on Umbar with a small fleet for a night attack, burning many ships and personally slaying the Captain of the Haven on the quays before withdrawing his fleet "with small loss". A night attack by ship requires substantial nautical skill, and losing ships in the retreat requires battle with ships.
We know also from "the fleet with black sails" that the ships of Umbar possessed sails as well as oars, and the free men of Pelargir using the Corsair fleet had sufficient skill to use the western wind to come quickly to the fields of Pellenor.
In fairness, after the fall of Numenor there's little evidence of sea traffic away from the coasts, but given the geography there's no practical reason to expect it -- there were no longer any accessible lands that required leaving the coast, excepting the elves' one-way trips. But that's a function of geography, not a Valar ban on the high seas or the lack of the ability to do so. Cirdan's mariners obviously had to be capable of high sea voyages, and Gondor and Umbar alike were descendants of a people which had routinely sailed across the high seas in both directions. We've already seen that Earnur's armada included ships of great draught, and that the Corsairs had masted ships with sails. At Pelargir the Corsairs main fleet included "fifty great ships", according to Gimli, to go with innumerable lesser ships.
Long story short, the world of the Lord of the Rings was absolutely, positively, peopled by those who had the skill and technology for high seas journeys, should they have a reason to do so. Even if you confine yourselves to the text of LOTR only, and there's no reason why you should, the sea-longing is restricted to elves, the one-way journeys are restricted to the elves, and the ban of the Valar only applies to crossing the sea completely, not traveling in it. Meanwhile, pirates (corsairs) are most certainly present, and have great masted ships that employ sails. Further, the Silmarillion says that after the destruction some Dunedain believed that its summit remained above the water as an island and some would even sail to try to find it. This is perfectly in line with the premise for the new cycle.
You are free not to like the theme of the new cycle, but please stop claiming it "reveals a complete lack of respect for the source material." It is firmly grounded in the source material, which has pirates, ocean-capable ships, sailing, and even legends of surviving bits of Numenor poking out of the water. Exploring the world of Middle Earth is supposed to be one of the reasons for the games existence, and I'm happy to see that the creators did not let some silly prejudice against pirates keep them from exploring an interesting part of Middle Earth.
Edited by dalestephenson