Nadal did have a "peak" and Shinoj doesnt know what he talking about. He peaked from clay season 2008 and there he was near unbeatable. But most great players at their best are near unbeatable because usually playing their best involves in a big way not letting the opponent play his best. Which is why you hardly see matches in which both great players play to their maximum best.
I cant talk about 2008 and so because that was the time i stopped watching Tennis.
But what i can gather about his game was that his only Rival,Federer had a big big mental Block about Nadal. It was almost funny. Federer would play his natural game in the first set till he leads 5-4 or 5-2 or so. Nadal would slowly turn the game on his own tempo by hitting, yes, Yours truly High moonballs on Federer's Backhand. And that was it. Federer would always play a catch up game from there, hitting the odd winners and eliciting symphathetic respnse from the crowd, but he cannot overcome the Ghost of Nadal, which is nowehere but in his own head, he wilts and folds up in 4 sets. And that happens in exactly all of their matches.
And there were no real rivals really for Nadal during those times. Murray was madly inconsistent. And there were odd Del Potros who came on sporadically enough to raise hopes but dissappeared as fast as they came.
This was my feeling about Nadal and his lack of competition during those times. however i might be wrong as i had mentioned earlier i didnt watch as closely as i did during earlier Eras. The lack of competition was appalling during what you say "Peak Nadal" times.
I say Peak Nadal never existed. He bought a playing style which nobody had seen before. A highly physical game with never say dies attitude which was imbibed by tony since he opened his eyes. Once that attitude was imbibed tony had to teach him basics of Tennis and cleverly he taught him playing Left Handed and playing with Topspin which was a remarbably ingenial move in hindsight. Some might think it as a Genius but i think he completely based Nadal's game on one of the greatest player the World has ever seen. Yes Bjorn Borg. The similarities are eerie. Borg played with a Never say die spirit. He played with a TopSpin and he played a waiting game. You can put your house, your car, you whole neighborhood on this that in future Nadal will come out and say that toni based his game almost on Bjorn Borg.
I can congratulate Toni/Nadal on their supreme planning and dedication but there will be only one Bjorn Borg, A player was a genius, who never had anyone guiding him fulltime, he came out like a lone force; dicdated the whole Tour to play on his terms. In short he was like a Napolean. He cam he saw he conquered. And in hindsight i can see so many players who have based their game on Bjorn Borg. Its remarkably uncanny.
For me these are the only true genuises who also reached sublime heights of the game.
Rod Laver, Bjorn Borg and Roger Federer.