D4 is not boring !!! I bet half of us would never be able to see through the complexities of the semi Slav and Slav proper from either side of the board not to mention the Indian defences which set up a battle between whites better center and blacks better pieces . a battle which lasts the entire game ( much longer than any one tactical slugfest) And then there is the Dutch which though little played could be considered the Sicilian of d4 land as there are many decisive results ! Also i would like to point out that the winning percentages in d4 land are slightly higher for white
Really agree! Playing d4 also train beginners to distinguish between positionaly good (or acceptable move) and horrid move. Intermediates benefits form selecting the best one among many non-forcing moves, and appreciate why "mainline" got its status or why some frequently played line in the past suddenly died out what's the merit of the replacement. (See Tarrasch Defense-- For black, losing one tempo or making a soft move before 10th move in mainline causes moderately quick dismay). For advanced players, they can find rich idea of play as both sides has wide choice of plan and perfect their accuracy in fine moves or technical moves.
As for winning percentage, it cannot be a certification of d4 is better. Yet, it shows that white got harder life with 1.e4, in practice.
I consider d4 and e4 to be slightly superior to c4 because c4 does not allow a bishop to move out and places a pawn slightly off-center. D4 and e4 are practically equivalent, but since e4 also allows the queen more room, I am inclined to say e4 is superior to d4.
e2 will not be occupied becaus it is in the way of the bishop, and won't really give the queen much scope. f3 will almost certainly be occupied by a knight in 1.e4 openings. g4 and h5 will both be protected by a black knight on f6, that is of course, those squares aren't already blocked by a white knight or bishop. Such a statement that the queen has more scope after 1.e4 is absolutely ludicrous.