Sorry for late response. Have other priority.
Your response confirmed what I think of your thinking. You want to have a clear standing/ ranking, but at the same time don't offer standard to judge them.
Football is a team game. Judging individual without taking tactic, how team approach never works. For example, Smalling can excel in certain type of games/ vs certain type of attacker. However, noone would wants him in game vs teams who never intend to come out & attack us but aim to disrupt our passing, since his distribution is subpar & his defending ability is just overkill/ uninvolved. In those games, Rojo along side Jones were better. The rank can suddenly change. Bailly for all his potential still inconsitent & inexperienced. Jones is similar.
The point is there is no clear cut between them & anyone can swing thus change the ranking.
Similarly is the standard of CB in PL in recent year. The gap in quality is too narrow. David Luiz had the benefit of the system that allowed him to play freely. He is the type of defenders with a wild style with skills set of both defender & defensive midfielder. The 3 at the back system cover for his tendency to leave the defensive unit & step into midfield (at times wrongly). Koscielny has Arsenal to play & defend on front foot. Against team Arsenal can't be afforded to play on front foot, he's exposed as not top notch in pure defensive job. Toby has good partners in his defensive units. Also has the & approach that offer enough cover: a defensive midfielder; energetic players even in attacking positions trying hard to help in defensive phase... Again when his team is outclassed by superior teams, he couldn't standout like a class CB should be...
Again the point is same: the quality gap between these guys is very narrow. In case we're on budget & have no mean to upgrade on someone like Rojo, Smalling... we're stuck to build a system to get the best out of them, then they can look up there with the best the league has in recently year. Smalling last year is evidence. Blind can match the world most expensive CB as ball playing CB... Rojo in his pomp when we set up the right way can perform to a level matching any of these best CBs in the league.
When I asked you for top 10, the meaning is to help you look out see the bigger picture. I was not trying to move the goal post.