I think you are misunderstanding how the South Stand will be used. Home fans WILL be behind the goal. The four blocks of the South Stand will be used as follows:
The two blocks nearest the West Stand are currently on general sale to home fans.
The block nearest the East Stand will be available to away fans but only if they take the full allocation of 3,300. If they don't then the whole of the South Stand will be available to home fans.
The other central block will always be for home fans and these will go on general sale at a later date. The reason they aren't now is because they will first need confirmation that Cardiff aren't going to need their full allocation. If a team does take their full allocation then a small part of this block wouldn't be able to be sold due to segregation.
Hope that helps!
I get that but I think it's odd that they didn't sell ST's in any of those 3 blocks .... or did they?