I agree, Robbie was none too happy (rightly so) when they decided that it was all for Cadel and not to worry about getting the sprint finishes. I personally couldn't see why they couldn't have gone for both...
Actually, in an interview before the Tour (or during, I cant remember) Robbie said that he knew Cadel before 2005 and he encouraged S/L to take him on given his talent. He said that at the time, he was fully aware over a course of 2-3 years, his ambitions with the leadout train would be dimished. He liked Cadel and he wanted S/L to build a team around Cadel and he knew that would mean at some stage he would have to leave. Robbie is a great guy, and he had control of S/L when they signed Cadel, so he couldnt be 'none too happy' when he instigated most of the goings on.
As for going for both. In the modern era - near impossible.
Teams that have joint prospects like that often will get 'good' results, but not the top step.
Garmin - Farrar, okay, GC guys, top 10s
Milram - Ciolek, okay, Gerdemann..hmmm
Columbia - Cav, great, no jersey, GC guys - struggled (same in 2008, stage wins for Cav, but Kirchen was alone)
Cervelo - Thor, awesome, but no support for Sastre
Cycling is so specialised now that having multiple options is okay, but you will never win both. Green and a Yellow in one year is just so rare that I can't see it happen again
Auscycle - as for your AG2R pick - that's quite interesting, they do have decent climbers, but I guess they may not have the money? It definately solves all leadership issues, assuming Valjivec is happy to work for Cadel.. might work actually the more I think about it