Not trying to challenge anyone :D
Forgive me if I speak too complicated. Even for me its hard to figure out what exactly I am looking for in this effect. With any card which looks on top of library any shuffling is just like Russian Roulette... Mostly its something typical for Blue color - The knowledge. Locally I have not met opponent who plays blue, except dudes who splash the color for counterspelling and Jace.
Shuffling was presented to me as an sideeffect which is designed to flush away knowledge about the card order in library when I looked on the cards during tutoring, a boring action with no real impact on the game because of its randomness.
I know how shuffling works with the Senseis Top, or much better with
Scroll rack. I personally had great but really random results from such combinations. But if I can shuffle more and more it works like a skeleton key which opens the deck. Thats exactly why I play
Esper panorama and similar cards. Less lands in library, possibility to shuffle and then lets look at the top...
The effect is random, very subtle, but cumulative and makes great difference during play - in EDH and Highlander its bit more bring new cards I have not met an opponent who will react on such action. (except for those who accused me of stalling).
But anyways, player who looks into his library due any tutor has opportunity to reshuffle poorly shuffled deck when cards are in bad order. Is it powerful? Surely yes, even when he decides to do normal shuffle without any cheating. Its the way how the (lets say)
Personal tutor works, however the "side effect" of knowing what might come can affect a decision if he shufflse the library more or less - thats surely not as random as it should be :D
Maybe it was certain to all players on this forum, but if a player apply his knowledge about his own deck to current state of the game, tutor any card, check the top of library he can gain an advantage in play, not because he searched for something useful, but simple because of shuffle. Its like ponder, but you are forced to shuffle.