Comments/Ratings for a Single Item

Larry, 
The problem with the regular pawns starting on the 3rd rank leaving the 2nd rank vacant (or filled with Ninja Pawns), is that this allows a double row of pawns which tends to clog the game  a bit I think. 
See Herculean and Hadean Chess in which the pawns are one row advanced with ninja pawns behind - its not too bad, but I was not too happy with that configuration in the end.
Many 10x10 variants do have start configurations with more than 2 rows but they normally use more powerful pieces not extra pawns. 
I think allowing extra pieces and pawns via gating/dropping allows more flexibility in the setup and keeps the original configuration more harmonious. 
Because the Ninja Pawns have to be dropped in the 2nd rank, the player is forced to move the regular Pawns first, thus favoring more aggressive type openings and advanced pawn chains. 
As it stands, the Ninja Pawns reinforces the pawn structure that can extend right towards the middle or even into enemy territory.

Did not mean for there to be an additional row of Ninja Pawns, only that the second row of vacant cells be available for the introduction of the five Ninja Pawns. Since this introduction takes up a move, the players might not do such until at least a few of the forward Pawns are developed.

Of course, moving the Pawns to the third rank will deter the forward development of the leapser. But with their additional step movements, they would still have as many or more potential opening cells.

Another aspect, starting from the third rank a few of the Pawns appear to begin the game undefended. Contrary to assumption, this condition is not a negative in itself. But with the ability to introduce the Ninja Pawn, technically they are all potentially defended.

Thus, one can develop a pawn, and then later drop and develop a ninja pawn (with attacking possibilities) in one turn.