Ok, one last comment then I should really leave it alone.
Sorry, I am not trying to be negative but I worked on a game that had drops for years and it turned out not to be viable for lots of different reasons.
Pawn Breaks
You need to be a strong player to fully understand all the implications of this, it is a fundamental part of chess at its very core. I will only give one example, please do not ask me to elaborate or give any further examples.
White spawns 2 Pawns on the E File
Black spawns 2 Pawns on the D File
Later on mass Pawn exchanges occur on the square D5
So now you have 4 open files instead of the usual 2 that would occur in chess after a Pawn trade.
That is just one example, there are many other reasons, I do not want to rake over past history and waste time man.
Starting with all the Pawns on the usual spots at the start of the game.
All been done before, looked at all that years ago, you will find it on google if you dig deep enough, please do not ask me, I am not interested in digging around trying to find stuff that does not work in practice.
Also, @Martin0, I very much like your "spawn 1, move 1" scheme. That seems definitively better.