Each grid point just has sends armies in 1 to 4 directions per timestep. So you have to visit each occupied square once per time step.

What is the sequencing problem? It's just 4 bits per square (send armies N,S,E,W).

That was a game changer for me. Sadly it exposed a major bug. Queue up enough commands it seems and the game gets stuck. Happened 2 separate times now for me.

It's happened to me, but I don't think it has to do with the number.

The biggest problem, I think (not sure) is that queuing is client side so latency matters.