I dont' see why people don't see this. Cavani is signing, not to be a back up for Martial or start over him, but to rotate with him. It's like Chelsea when they had Gudjohnson and Drogba. At the time, neither were world class in the way Henry or RVN were, so Chelsea decided to have both constantly rotate with each other. Both scored about 15 league goals each, getting 30 in the process. It's similar to how we used Cole and Ole in the treble team. Cavani playing for us, means Martial has less pressure to be a 30 plus goals per season striker. It makes our attack more consistent.
In addition to this, he provides an option out wide. This means that we now have two players capable of playing on the right side with the quality to be impactful in every scenario in Greenwood and Cavani. At the start of last season, we had Daniel James as the only player willing to play on the right, as neither Rashford or Martial has shown any signs of wanting to play there. It means that we have options in case of injuries, and even with the signing of VDB, we can also use him across the attacking midfield line, we have options. In signing Cavani, we would have fixed our biggest problem last season, attacking depth. We could never trust ourselves to rest players because we knew that we have lingard, mata, james and pereira to replace them. Now we have VDB and Cavani, with mata ocassionally. That is a massive improvement. If the idea is for Greenwood to grow into the right wing position, this is a huge plus as cavani can mentor and rotate with him.
Our two other weaknesses are, full back depth and the centre back next to Maguire. In terms of Maguires partner, I do not feel we need to sign a centre back unless a really high potential one becomes available. We have Mengi and Tuanzebe coming through, with Bailly potentially providing a stop gap. The centre backs available are not impressive, especially considering their inflated fees. For example, I do not think Upemacano is much better than Bailly given the technique and defending I've seen from him. He is clearly not 40m more than him, but that is the price to sign him in the current market. We may as well push and develop our defenders quicker. None of City, Spurs, Chelsea or Arsenal have good and steady centre back partnerships. And even Liverpool's Van Dijk has a weak partner. In addition to this, across Europe, I don't believe too many top teams have centre back partnerships better than what we can potentially have. We all saw Varane against City, the issues of Pique and Umiti/Lenglet. Even De Ligt had issues at Juve last year. Patience may be better for that position. In terms of full back depth, most teams do not have it. And for most teams it makes sense as their full backs are usually fit enough to play the whole season. Unfortunately for us, Shaw has been injury prone due to consistent lack of fitness. And as a result, a suitable left back who can rotate or replace him may be necessary unless he shows otherwise. Williams is not good enough, and I'm not sure he ever will be.