Silva staying could be helpful.
Another big problem is just who you are up against. Competition is fierce now in this league. City will be City, the hope is that they might drop back a little after losing guys like Gundogan, but that tends to be wishful thinking.
Then guys like Klopp and Arteta have been in multiple years and established style of teams and patterns of play etc and look like adding well to their teams.
Utd will be into their 2nd year under ETH and if they get guys like Onana, Mount and a striker, should allow them to evolve even more into his type of team, and Newcastle look like they are adding quality as well and will continue to evolve.
Spurs will be a bit of a wild card, and I fancy Villa to have a good season with a full pre season under Emery.
So, as much as I think Chelsea will defo get better, they don't get better in a vacuum, and are almost playing catch-up to the rest now. Should certainly be a lot more exciting to watch this season that's for sure.