Yeah, Watson has been shafted his whole ODI career with his batting. No wonder people think he's no good. It's no wonder when you stick the guy who is least suited to #7 at #7. I'm not sure how he'd go in the #4 spot, but it may be worth the experiment as it would give him time to settle and that's something Martyn benefited from. I guess it just depends who else the selectors would like to include. If it's Hayden/Jaques, then he may be shifted to 4 (or most likely 7, given his treatment in the past aarrrgh). But if they want Voges or White, he could stay as an opener.
Hussey gives them that flexibility, and I hope they float him a little bit more. If they lose 2 quick wickets, he can come in at 4 and play like an opener, blunting the bowling, but if they are flaying them up the top, he can come in at the 40 over mark and hit a quick 50.