I feel it would have seriously unsettled both Martial and Rashford (and I love them, would hate that to happen), since Mahrez is about 25, if I'm not mistaken, whilst Sanchez is 29, so we can expect to see 2-3 years of his peak and allow our young stars to develop in the same time.I don't know why u didn't go for both. Sanchez left and Marhez right would be awsome, yes I rate Martial but he's not there just yet and Rashford could have been a proper backup for Lukaku.
Still, hope we start playing more to our strengths and I believe any of our attackers can come good in any position, as long as the team plays cohesively.