Hm. I'm always wary of this kind of "You've been doing it all wrong" article. Here comes another one who knows the best way for everybody.
While you can find parallels with anything if you try hard enough, I think music can hardly be compared to baseball. Or maybe playing the clarinet can, it looks more like a bat than the piano
But I do not see why repetition (or rather, repeated practicing of passages) would be so boring. It would only be boring if there was no progress, in which case you might as well not do it. I find the slow process of improving through repeated practice very engaging and rewarding. It is true of course that practicing one passage should not be done for hours on end, or fatigue and frustration will set in. But to sit down and make a scheme to rigidly chop up practice sessions in 2-or 3 minute snippets, then going to the piano with a piece of paper and a clock, that
would bore me to tears in no time (heck, the very idea bores me to start with) and take away all the pleasure in the music.
But hey, perhaps it will work for you, and make your Scarlatti perfect in no time