Your point is valid, and you gave suggestions as well.

I agree with you that machines should not talk on the HTTP level, it's over kill. Machines only need very simple protocols to exchange current state if they do need to cooperate. To me, if devices can transfer state with the controlled program should be good enough so that the program will send the states to other machines for them to determine what's going to be the next step or directly give them instruction on what the next step to go.

I know it's a lot fun to build this type of cute machines, but it's not economic.