I have already stated that all it takes is a deterministic function to be applied to the current order of SHs. The only way to affect the outcome of this function is continually add or remove SHs from the equation. Adding costs significant amounts of money, subtracting has penalties in both power over the system and early withdrawals. There is no infinite possibility scenario for the attacker to perform. New joins will be added in a deterministic manner that has nothing to do with the public key.
Sor.rge, do not allow yourself to be derailed by what AnonyMint thinks is necessary due to his lack of competence.
Show where the entropy for that function is stored and who is decided that it is stored. Then you will see that you haven't solved the problem. You will see that decision can't be made without having the order randomized in the first place, without opening a hole for gaming. It is a chicken-egg problem.
In order to collect several joins/leaves (deposit transactions) to take away control from the single transaction targeting I have alleged, you would have to have CB, but still the last TB can game this function and knows it a priori. You (and mobodick) alleged upthread that the choices would be so limited so as to not be reasonably gamed, but attacker has many options into the distant future. The attacker only needs to target clustering his SHs in a consecutive order in any future CB so attacker will have numerous opportunities (every CB until that future CB), and then once he has all in a CB or nearly all, he can really take control over this function and assert continuous control.