How to fill Candidate spots?

Recently, the chess world has seen the phenomenon of calling the world champion to be underserving of the position (e.g.: Ding and Gukesh). Does this mean that the strength in chess is more volatile than in the past? While this theory cannot be disregarded, it is painfully clear that the problem lies elsewhere. To anyone that cares to give attention, it should be evident by now that the fault is with the way Fide fills the candidates spots. It is reasonable to say that the current way Fide fill the Candidate spots is a joke (see this for recent controversies). For example, #3 Caruana made it to candidates via last year's Fide circuit (sure, he would have played more events, or would have played more tenaciously if he didn't have that path). I don't understand how last year's circuit winner is relevant while last world champion and average rating are not (note that the rating path requires one to prove activity unlike last year's circuit). Needless to say, 3 spots going to top 3 in a single elimination tournament is a huge blunder.  

My recommendation would be as follows. 
[A] World championship runner-up: 1
[B] Grand Swiss: 2 
[C] Fide circuit: 3 
[D] Rating: 2

Note 1: Grand Swiss is a proper classical tournament unlike World cup. So, giving a spot via World cup sounds wrong to me. I think the world cup is too volatile as a measure of player's strength in classical chess. If one is adamant about giving spots via World cup, it should be only spot (simply because the 2nd and 3rd positions depend highly on the initial pairing).  

Note 2: If the runner-up in the last world championship match is too weak to be included, that means the last world championship match and probably last Candidates field were weak, which needs fixing anyways.  

Details:-

[A] World championship runner-up: 1
[B] Grand Swiss: 2 
[C] Fide circuit: 3 
[D] Rating: 2
[It is to be understood that in each path, players not qualified via paths listed above it are to be considered]

[C] Fide circuit: 3 
(Among players not qualified via paths A and B) top 3 in the [2-year long] Fide circuit. 

[D] Rating: 2
(Among players not qualified via other paths) two highest-rated players  according to the 6-month average classical Fide rating, provided they have sufficient activity facing similar rated players  (I suggest the following criteria to evaluate this: in the 6-moth period, at least 20 games facing opponents of rating greater than 0.925 X, where X is the rating of the player at the start of the 6-month period).