ManU are simply SIGNIFICANTLY better without kaku and sanchez. They just don't fit the model of extremely quick (acceleration), quick decision making, and highly technical attackers. They already got 80M + ~7M/yr off the books with Kaku. If they can offload Sanchez's salary + 15-20M, that'd be pretty good business getting rid of those players.
That said, Rashford really needs to take the next step next season, like Sterling @ City. He is a much better natural finisher than Sterling but has been pretty awful this year. Quite frankly, has the tools to be a much better player than Sterling.
Yeah, Martial, Rashford, Greenwood fits the team better than Lukaku, we dont even cross the ball much now. It's more through ball and quick counters.
Rashford had very good season tbf then he got awful injury which ruled him out for the rest of the season in Jan, I don't think he is playing to his full potential (physically) after the restart, he has become more of playmaker than the player he was (always taking on defenders). His passing has improved a lot but he should start to combine this with how he played before, take on defenders and go for goal. I think he is still taking it slow as he has just recovered from serious back injury.
For me the biggest surprise is Greenwood. IIRC I posted about him few times but I never thought he would step up so quickly and so awesomely. Before the lockdown, he was fragile boy, now he has added muscles and looks very strong player. For youth team he used to score free kicks from both feet and he is proper two footed player (like 51 vs 49 left footed)
This season has been mixed bag with so many injuries. We lost Pogba for almost whole season, Shaw missed few months, Rashford and Martial missed few months. We started the season well and then pure crap with great games in between. Bruno just changed the season completely. He is proper Ole player, I remember in one of the interview with Neville Ole said he don't want players to pass for the sake of it, they should try to move the ball forward quickly, Bruno is perfect for that. Every pass he receives, his first thinking is to hurt the defense, no wonder his pass completion is always around 75%.
Lukaku deal is win-win for both clubs IMO. We got rid of player who didn't want to be here, which means Rashford and Martial were sure starters and also more chances for Greenwood, Inter replaced their goal scorer for good fee and also player who was always wanted by Conte.