Points one, two and three I absolutely agree with, and would also like to suggest that our corporate "partners" are offered "corporate" tickets in an appropriate area of the ground, ie with other corporate customers in the boxes and suites of whichever ground the match is at.
However, please see the below in response to points 4 and 5. I think SC's get an unfair rep because people don't truly understand their processes and services, especially when they themselves are not part of a SC branch or have mis-understood the intentions behind the service that the provide.
All supporters clubs are, are a vehicle/service that people use to apply for match tickets. The supporters club in question will take on the responsibility of sourcing those tickets.
The method behind sourcing the tickets is exactly the same as when a group of mates want to go to an away game and sit together. One of the group buys tickets for himself and the rest of the group by using his and their season card numbers providing all of the group qualify for tickets by having the right number of loyalty points.
As a member of a SC myself, I have only been successful with my allocation through the SC when I have satisfied the Loyalty Points criteria.
On occasions I have missed out on tickets because of not having enough points, and when this has been the case, I have (on the rare occasion) been able to source tickets through friends, or other members of the SC who have the correct amount of points and are happy for me to use their season card to source a ticket. It's important to note the latter is NOT a process of the SC and is just a pure consequence that being a member of an SC offers you, by increasing the network of match going fans that you know and can contact should they decide to not go to any given game for whatever reason.
As long as point 5 is policed correctly, (and how you go about doing that, I have no idea) then there is absolutely no reason to ban SC's from getting tickets, as stated all they do is deal with the logistics of getting tickets so that their members don't have to, and to ensure that as many members of the branch can be sat together as possible.