I've always thought Lincoln was overly confrontational and that he helped plunge the USA into its most damaging war. The reason he's remembered as a great president is simply this: His side won.

If they'd lost, he'd be remembered as a catastrophic failure.

That's the way it works with national leaders and wars. The winners (like Churchill or FDR) become heroes and saints. The losers get blamed for everything that went wrong. In either case, the public perception is usually an exaggeration of the reality...often a pretty extreme exaggeration at that. Wars between sovereign nations are usually won by the side that has more people, more money, and more resources....regardless of who the leaders are. When one side is is badly outmatched in men, money, and materiel, it loses.

That was the case with Germany and Italy and Japan in WWII. It was the case with the South in the American Civil War. They had almost no chance at all of winning that war in the long run. Lincoln could have been a mediocre president, and he'd still have won the Civil War...as long he didn't lose the will to keep on fighting it.

(In that respect, however, he was the right man for the North, because he was as stubborn as could be about persisting in fighting that war to final victory, no matter what the cost in lives and destruction. Others, like McClellan, might have negotiated an armistace partway through, and the South might have remained a separate nation in that case...at least for awhile.)