It seems to me that Plummer might have been too old for the role, seeing as how in 1965 when Chimes was made, he would have been about 36. At the beginning of the story Prince Hal is supposed to be about 16; about 17 when he slays Hotspur, and about 27 when he becomes king and rejects Falstaff. Plummer's character in the 1965 Sound of Music, Captain Von Trapp, actually has a daughter who is 'sixteen-going-on- seventeen'. In fact, one could even argue that Kieth Baxter, at 31, was a bit old for the early scenes too, but then he looked a lot more boyish then Plummer probably would have. I think Plummer would have made an excellent Hotspur, and again, although one can hardly quibble with Norman Rodway's performance, Plummer as you mentioned, would have provided more star power.