We have a workhorse CB in Dawson, unless we are going to upgrade him then keep him, Fonte is a downgrade, a big downgrade
Really? I think Dawson is better individually, but the best individuals do not necessarily equal the best team.
Particularly in defence, you need to build a unit, not a collection of individual defenders. It's better to have four players who are individually worse defenders, but who have a good understanding together, when to stay, when to push up, when to go towards the ball, when to stand off, when to fill in for each other etc.
Fonte has proven himself in Poch's system, a high intensity pressing game holding a high line.
Dawson has noticeably struggled in this system. AVB compromised his system to accomodate Dawson and in the friendlies we've played this summer, Dawson has looked undoubtedly the weak link. That's not to say in the right system, Dawson isn't an excellent defender. He's a stopper however, he works best in traditional English systems, such as that employed by Redknapp in the season we finished 4th the first time around, where you had a 4-4-2 with Dawson the stopper and Bassong the sweeper.
Fonte vs Dawson doesn't seem like an upgrade, but when you consider the tactical implications of each player in the system we plan to be playing, then it might be a transfer well worth doing.