They won us MUCH MUCH MUCH more games then they lost us. Before Barca game Higauin had 6 games in a row where he scored, and only last week he won us Napoli game. With virtually ONLY shot he had. Dybala spent first 2 months of the season being our personal superhero, missed pks, and seems down currently, but he is still our most important player.
Neither is comparable to Mandzukic, who currently isnt doing enough, his workrate/defending isnt as before, and with Costa here it shows us even more how limited we are in the wing creating/taking players on on that left flank with Mandzu there, so what extra advantage does Mandzu have left there? be a presence in the box and finish off chances, but guess what? Mandzu missed 3-4 chances last night. Us going without scoring and getting 3 pts is on him because he got virtually all the decisive chances in this game besides a Khedira chance.
So YES, Mandzu has no bussiness being compared to Higauin.
And if his impact remains like this, he should not start over Costa. Especially in 4-3-3 that requires strictly attacking qualities from the LW, and not like in 4-2-3-1 which requires Mandzu's style more due to helping out midfield more with defensive work. But 3 CMs do not need that extra aid.