I truly think Evan Hansen is the toughest role in Broadway history. The fact that Platt knocks it out of the park is such a testament to his unbelievable talent.
Aimee in SCANDALOUS. You are on stage for most of the show singing in most of the numbers, you get to play the character from her teens through her 40s, and you get to perform some of the worst material ever written for a musical. That's gotta be hard..
HamilHansen said: "Anybody say Anatole from Great Comet yet. Stratospheric high notes while dancing and moving and acting charismatic the whole time..."
You realize you commented on a 10yr old thread right?
In 50 plus years of attending performances, there are two that stand out in my mind, both early in my viewing experience:
-- Barbara Harris in The Apple Tree. I saw parts of this 5 or 6 times, partially because this was the perfect show to sneak into for Acts 2 and 3. I was always in sheer awe of her ability to get through the show. Interestingly, somewhere in the run she cut down to 6 performances, with Phyllis Newman doing matinees. I always assume this validated my 16 years old's assessment that the role was a monster.
-- Joel Grey in George M. When he wasn't singing, he was dancing. When he wasn't dancing, he was singing and dancing at the same time. Tap dancing quite a lot, as I remember. I also remember thinking that it must have been very frustrating for him to be killing himself for a show that was really mediocre. All that energy for a misfire.
Others more recent than the Stone Ages:
-- Mama Rose
-- Evita
-- Evan Hansen -- absolutely, unquestionably
-- Peter Allen in Boy From Oz...I may be exaggerating this now, but I couldn't believe how big the role was, how 'intimate' the character had to be with 1,500 people in the audience if he was going to entertain them, since the show itself was atrociously inept.
-- Sweeney Todd
-- Max Bialystock...just Betrayed alone is an endurance test for a role that has already had him rolling around on the floor, shouting at the top of his lungs, etc.
-- Coco...I remember thinking that Katharine Hepburn didn't do anything half-assed. If she was going to star in a Broadway musical, the audience was going to get its money's worth.
-- Fanny Brice
-- Arthur Kips in Half a Sixpence. Huge role, constantly dancing. I remember the Tommy Steele, who was in his late 20s, was soaking wet from about 15 minutes in, and he was in his 20s.
-- Diana in Next to Normal
That makes ten. I am sure that I am forgetting THE absolutely hardest role, but the above are pretty daunting. Only saving grace: at least 4 of the roles above are to be played by people in their 20s.
Definitely Peggy Sawyer as well. I recently saw a couple of scenes from a high school production, and the amount of tap dancing and singing needed for the role is immense. I can only imagine what the role is like for seasoned professionals, not to mention students.