It's generally thought that the Singapore Suites are best for a couple as you can put the center divider down and make something like a double bed but you mentioned that it may not be desirable for you. You would also have to have Krisflyer miles to book that.

In that case, anything side-by-side would be good. Pre-deval by United, we flew LH F on the A330 and it was easy to conversate. Australia is going to be tough to get two good seats. Have you looked into Virgin Australia using DL miles? I'm not up to speed on their seats but I know they had front-facing business class seats. They weren't fully flat but you should be able to get seats that make it easy to talk and interact.