I agree, but the fault lies not with Grant, but with McClellan, who could have ended the war smarter in late 1863, rather than dithering until Grant had to respond to a rebounded ANV in late 1864.
P.S. The reason Custer, Napoleon, and Crassus--and I would include Darius in Greece, and Hitler at Stalingrad to the list--were losers was because they were the aggressors, meaning they started the war, and aggressors are successful when they follow Sun Tsu's tactics, rather than simply pushing pedal to the metal and hoping for the best. Defenders, OTOH, have to slaughter-and-burn the aggressors, so that the aggressors decide it isn't worth it anymore and either surrender or go home, which is essentially the same thing.
McClellan sure did waste chances. IMHO, the biggest gamble that paid off in the Civil War was Chancellorsville for Lee. I don’t think the tactical genius and timing of everything that happened there can ever be replicated.