[alatar]

• It was an arm's race - predator and prey sort of thing. If Sauron regained the One Ring, the prey may not have the time to adapt.

• It was just PR/spin. The Wise, seeing Sauron rising again and contesting their hold on the world, decided that whipping up the troops with, "If he regains the Ring, then we'll have to go back there again and cut off another finger, and wasn't it so boring the first time?" wouldn't be as successful at raising an army as it was the first time.

• Sauron learned from the mistakes that he brashly made the first time, and so this time he had a better chance of getting it right - less elves, less Men of the West (and he hunted them), poorer weaponry, better soldiers (Olog-hai), the fall of Minas Anor and Osgiliath, the recession of Gondor's control of the south, etc. What he didn't add in were the hobbits.