They could just cover the last major event of the Second Age - the War of the Last Alliance - but that'd miss out the other major events which could easily have seasonal arcs, or even multi-season arcs (the creation of the rings, the war between Sauron and the Elves, Sauron and Numenor, the Akallabeth, then the War of the Last Alliance). Footage so far, as well as the casting, indicates that's not what they're doing; but I worry they're going to try and condense all the significant events of the Second Age into the span of a few years which, for me, is a point of concern.
The major events of the Second Age take place literally centuries apart, which was always going to be a challenge for an expensive show aiming for a large audience. The rings are forged roughly 1600 years into the Second Age, at the Elven Kingdom of Eregion, which borders Khazad-dum and is just west of Lothlorien. Sauron, re-emerged after centuries of hiding following the defeat of Morgoth during the War of Wrath at the end of the First Age, assumes a fair form and fools the Elves at Eregion into working with him to create the rings (Gil-Galad and Elrond in Lindon, on the west coast of Middle-Earth, refuse his advances, as does Galadriel in Lothlorien). When the Elves realise Sauron plans to enslave the ring-bearers, it's too late - Sauron invades and destroys Eregion, recovering the Seven and the Nine, while the Three remain hidden from him. Celebrimbor, creator of the rings, is slain, and general war breaks out between the Elves and Sauron as Gil-Galad rallies the Elves of Lindon to fight against him; Elrond is forced to retreat to the valley that becomes Imladris/Rivendell, and the situation for the Elves looks grim - until Numenor intervenes and helps the Elves win this first war. That whole plotline could easily be fleshed out - Numenorean politics (tensions between the Elf-friends and the people who envy the immortal races), the Elves and Dwarves forging an alliance, tensions between the Elven leaders over Sauron and his intentions; climaxing in the actual war and Sauron's first, temporary defeat. Sauron's defeat at the hands of Numenor is key here - he fears and despises Numenor (hence his fear and hatred of Aragorn thousands of years later), and resolves to bring about its downfall; but he knows he is no match for Numenor in a direct confrontation.
The next major events pick up like 1500 years later. By this point, vast changes have taken place in Numenor's society - no longer peaceful explorers and friends of the Elves, they are now conquerors, having established what are effectively colonial outposts in Middle-Earth, waging wars or persecuting the 'primitive' men they find there. Numenorean rulers and nobles become more and more frightened of their impending death, clinging on to their lifespan instead of departing 'gracefully'; a key idea here is that, in earlier ages, Numenoreans lived for a couple of centuries, but aged gracefully, and died willingly while still in good health. The nobles who cling to life become increasingly unwell, physically and mentally, and this manifests as an envy of the Elves, and an increasing suspicion of the Valar, the immortal powers that have informed the men of Numenor to never sail to the Undying Lands. This shift in Numenor's society would be impossible to depict in full on screen; you can't show all of those many centuries, but the passage of that length of time is really significant: it's that passage of time, and how it's experienced, that drives divisions between Elves and Men, and it's that difference which allows Sauron to act as he does. Elves remember Sauron's evil and betrayal directly; for Men, Sauron's actions have become remote history, generations back. Between fear of death and pride in their own strength, Men underestimate Sauron and force him to return to Numenor as prisoner. Sauron's presence corrupts Numenor over years, before he convinces the ailing king to attempt to invade Valinor. Naturally, attacking the powers that be is a terrible idea, and Numenor is destroyed.
Personally I'd hoped you'd get a couple of seasons in the earlier era of the Second Age showing the creation of the rings and the war for them; then the showrunners could be brave, and jump forward to the later era. The Elven cast would be the same (Galadriel, Elrond, Gil-Galad are present throughout all the major happenings in the Second Age); the mortal cast would naturally need to be different, but we'd see a later, evolved version of the Numenor we were introduced to as viewers in the earlier seasons. The final season (or two) would jump forward one last time, by a century, when the War of the Last Alliance happens (yes, that's right - there's a century between the end of Numenor and then the end of the Second Age).
My personal hope was that they'd treat each of these major events as the basis for a season or two of material; begin with Sauron's appearance, the events that lead to the creation of the rings and the war for them; then move forward to Numenor's gradual downfall; then finish the show by focusing on the events that comprise the War of the Last Alliance. The key swing of the Second Age is that of the friendship of Elves and Men waxing and waning; Numenor is founded as a refuge and reward for the Men who fought the hopeless war against Morgoth alongside the Elves; at one point, Numenor is the key ally against Sauron for the Elves; then the two peoples gradually diverge, as later generations of Men become both prouder and more afraid (therefore easier to corrupt), distant from the Elves, even turning on the Valar at Sauron's behest; the remnants of Numenor found Gondor and Arnor and the Last Alliance.
I guess my fear is that, with a radically condensed version of these events - with them happening within a few years or even a few decades - you kind of miss the point here. Men change, forget, and fear death; Elves remember, linger, and preserve. That fundamental difference between the two peoples creates powerful alliances but also leads to a great distance between the two races that Sauron exploits.
I've seen enough from the cast list to know that what we're getting has radically reworked the timeline of events. While I understand why the showrunners have done that, I am a little concerned about what that means, and I'm a bit concerned because I wanted them to be braver and to embrace the grand sweep of the Second Age and really try and capture that difference between mortal and immortal. But I won't go into specifics on casting etc because I know people avoid that information to avoid spoilers sometimes.