Im just gonna say what i think.......

Rommel was an excellent leader, He was always on the move and always got the best out of his men. But he wasnt all that good with dealing with Hitler or the italian Generals.

Difference between Rommel and von Manstein is that Rommel took risks. Usually his risks payed off, When he first arrived in NA, with the few men and tanks he had he pushed the British back, He didnt bother waiting for all his men and equiptment as he was ordered.

Honestly had been given 2 full strength armoured divisions and a few motorised divisions and allowed to do his thing and they sent in some one like von Manstein to deal with the Italians and Hitler etc then i think Germany could have won in NA.