Chelsea
Losing Kante, Hazard, and Courtois would be major blows, considering their influence and status as world-class players. Getting top replacements may be difficult, considering their cost, and the change in strategy by Abramovich. It seems he's not as willing to splash the cash as he once did. Chelsea would still be a threat, and still hold top players, but Sarri has a season of rebuilding as well possibly working under a historically reduced budget.
There is also talk of Petr Cech returning from Arsenal, which would be a boon considering his status as a Chelsea legend. Nonetheless, he's not the keeper of old, and despite his status as one of the top PL-era keepers (alongside Schmeichel and Seaman), he has made numerous errors in the last season with Arsenal. He may not arrive, if the rumours are true, as a number one keeper, and securing a world-class replacement for Courtois has to be a priority.
With a change in transfer policy, Chelsea may need to promote from their winning academy or get mid-range players to succeed. Spurs have done this, and Arsenal is following suit. Man United have signed Bailly, who was not world class per se. How Chelsea manage in this new paradigm is key in their future seasons and this close season.
Rating: 6/10
Retaining and replacing top players is key for Chelsea.