[The 1,000 Reader]

Stretching out the thread's question a bit, I'll cover better options for all of Sauron's conflicts.

Isle of Werewolves

When Luthien announced herself, Sauron should have looked out the large window overlooking the island (and if that failed, turn into a hawk that would be hard to see) and try to spot any surprises she might have brought with her. After seeing Huan, Sauron could have done these things:

1. Swooped down low on/in the wind that wouldn't carry his scent to Huan, turn into his large vampire form when near the ground, and like in Jeepers Creepers 2, swoop Luthien up quickly and take her to Morgoth for a reward.

2. Sent out his wolves in large number (all at once, I might add,) and observe battle from window to see if Luthien had backup or was putting up a good fight. If Huan wasn't injured too badly to fight from the wolves (not killed, due to the prophecy,) Sauron should have taken his werewolf form, gone out to fight, and not have attacked Luthien when Huan dropped his guard and leapt aside in terror. Even if everything else was like the books, he likely would not have failed if he didn't waste that opportunity.

3. Gone out there himself in werewolf form, attacked Huan when he dropped his guard and his spirit faultered, take vampire form and fly to Morgoth with Luthien in his clutches.

Numenor

Ar-Pharazon would likely attack anyway, so all that could be done would be to keep the orc-hordes calm so that they wouldn't panic and abandon their master, so that they wouln't have to be found and re-recruited. Numenor was already down a dark path, and Ar-Pharazon would probably appoint the first guy that fed his ego (or just bring Sauron to a higher rank so that he could display him as a "trophy" for his ego,) so the same role in the books would be alright, but with less attention drawn to himself and an attempt to make it look like Ar-Pharazon chose those actions alone. When Numenor attacked Valinor, retreating to Mordor would be a good maneuver in case the Valar took major action or prayed to Eru, which would be very likely considering the circumstances. Forces, large yet small enough to avoid the elves, would be littered along the Anduin in the event of any faithful Numenorians fleeing from a potential catastrophic event caused by higher powers.

Last Alliance

A possibility here would be to make sure the elves and men never formed an alliance to begin with, so, if powerful enough, attacking the elves while Numenor assaulted Valinor would have a chance of success. If the alliance formed with such power anyway, a tactic of refitting Barad-Dur with siege engines and numerous places for archers to cause havok could bring positive results, though the credibilty of the tower's "invincible foundations" would play greatly on this. A strategy of sending an army to face the Alliance while another force approached from the rear might be applicable, though the LA could easily do the same. For Elendil and Gil-Galad, anything from simply turning them to ash with the Black Hand or making lava from Mount Doom fly at them with incredible speed and accuracy would work. I mean, honestly, these two aren't packing the strength of Feanor's family, and they don't even have a prophecy behind them.



War of the Ring

Getting some orc hordes to steal a map of Middle-Earth off of a dead ranger and making Gollum point to where the Shire was may have worked. Simply sealing Mount Doom could also yield results, though if he was still blinded by arrogance and wouldn't sealed the way just to be careful, he could have tried to make the mountain erupt and rain lava, stone, burning stone, and etc. down on places such as Minas Tirith, sealing up the way into Mount Doom so that none of the stuff would "leak" onto Mordor.

Those options out of the way, the hosts of Dol Guldur could have been turned to other matters, reacting to Lothlorien only if Lothlorien made the first move. The elves of Lothlorien seemed rather uninterested in the rest of Middle-Earth, so leaving them alone unless they bothered Sauron's armies would work. More orcs could be diverted from Moria to help Saruman, and even declaring war on Rohan to assist Grima's slaughter of Theoden's morale is an option, though actually attacking Rohan does not need to be done. Finally, using half of the Mordor host to help the Morgul host for an assured victory is on the table.