we've now gone beyond riyaaz of basic raagas to generally putting in hard work in refining and honing in on one's craft. i'd have to be crazy to argue against the latter. most folks who succeed generally work hard, though reverse is not necessarily true. but the issue i had was with working through the same riyaaz day in and day out. that is where i thought we were getting into the realm of being too rigid- for folks who need that discipline perhaps it's the best way to improve, but certainly it need not work for others.
in school, we had folks who were very good at multiplication tables because that's what they did all day. did not add to their ability to solve advanced problems. in college, i can recall "muggus" who would spend all their time cramming up formulas on a daily basis, or later cramming up all the vocab words for gmat/ gre. they never did as well as some of the others who had a basic intelligence in such areas. i dont know what it is but too much structure has often been found to be limiting.
As for the various examples some folks have cited, basic question is this. can we be sure that their greatness stemmed solely from riyaaz and not from their inborn talent? a lot of folks do riyaaz everyday, but not everyone makes it. we might be just looking at a sample where the folks started with loads of talent and their riyaaz was the proverbial icing on the cake. given insufficient data, it is hard to derive any conclusions as to what was the deciding factor behind their success- but hard for me to believe it was just riyaaz.