I have not watched Raja Hindustani, which I don't plan to unless I have to watch a double bill of that and Hum Aapke Hain Kaun?, if you get my drift. Nor have I watched Raakh, which I hopefully will some day.
The kind of characterization that Aamir Khan has had in many of his roles usually have him as the pro-active protagonist, not one who is introspective or brooding or reactive to situations. He usually is a smart-alec or atleast one who has the ripostes in the film. His character is usually overbearing, over others in the film. Even in his one role that had dark shades (1947-Earth), the role fits in more or less with the above descriptions. In short, he has not enjoyed the variety that he probably deserves. It doesn't matter if the role was a success or not, but the drastically different role has yet to happen to him. In that sense, his "much awaited" Mann (Current BC-ians would get that) was his only risky venture for it showed how much he would bend over to help his brother! Of course, he has shown flashes of emoting different emotions in the many films he has done, but nothing substantially different on the whole. Perhaps, with his productions, he might have more choice.
I've always maintained that it was a shame that stars like Amitabh didn't have the guts or perhaps the inclination to experiment with roles. But atleast in Amitabh's early years, he had the fortune of obtaining meaty or diverse roles from Hrishikesh Mukherjee in Anand, Abhimaan, Namak Haraam and even, for those who remember, Alaap. He could've made a difference in the 80s when his word was gospel, but didn't exercise that power. Much like Rajnikant these days. These supermegaultra stars seemed locked into a self-perpetuating cycle of the same plots that got them to the top. Hopefully, Aamir Khan will enjoy more dare-devilry in roles.
On a related note, I still find it hard to believe that Lagaan's Bhuvan was first offered to Shah Rukh Khan. Perhaps the other great friendship of Gowarikar led to that rather intriguing casting call, which Shah Rukh Khan declined then. Anyway, Shah Rukh & Gowarikar have their opportunity to show how it might've been with their newly announced Swades.