I wouldn't rule it out completely, size does not dictate over all capability always. I would think they would use the extra space for helos rather than 32 VLS. We will have plenty of VLS if every Anzac II is carrying 48 VLS anyway. The white paper did specifically specify 7,000t. They could be larger if more lightly missiled.the F100 is an intersting design if you can just add peices to the middle of it.
leave it be if you want a frigate, add 1 if you want a destroyer add another 1-2 if you want a cruiser, add 10 if you want a Battleship
i doubt the RAN could convince the government to go for it tho, being their supposed to be frigates, dont think it would go down well if they're more powerful than our destroyers
Although I do wonder if an "Australia" class AWD with 48+32 VLS + Harpoon and 6" gun with 2 vessels would not make for for a strong addition to the RAN. But perhaps this is polishing a old and limited design a bit too far, perhaps a fresh approach would bring more value.