This isn't so much a bug as it is a way to speed things up (probably VERY easily):
The economic phase is played sequentially in the game currently. However, there is no reason this has to be this way. There seems to be a "pre-economic" phase that happens anyhow (including the collection of money and manpower, victory point collection and that sort of thing -- all the automatic stuff). The only things the players really need to do is buy troops and counters, set manipulation, etc.
All of the things the players need to actually put their fingers onto can be done independently from each other. There's no tie-in (except for giving money, but that happens in the diplomacy phases). So, all seven economic phases could be done asynchronously, without any impact to game play other than not knowing which countries built how many ships, and if any other nation made a kingdom.
If you decide to use this idea, and thus give credit for this one, please include gwheelock, as it was a conversation we had together that got us thinking about this.
It is not a bad suggestion, especially if some reactions/answers that are normally part of the diplomacy phase could be lifted out to the reinforcement phase, mainly change of movement order and responses to offers of alliance.
The alliance request is a bit more dodgy than movement as new alliances could shift where you want to place reinforcements, I personally dont think it will have any major impact on game play.
It could also open up for a possibility to resolve things like peace treaties and access requests interactivly in the reinforcement phase. Something that could be interesting, and make the flow of the game more like the boardgame, without slowing it down. This needs careful thinking though as it may have substantial impact on gameplay.
My post refers to the economic phase, not the diplomacy phase. This would be in addition to the changes you suggest for the diplo phase.
At LAST! The greatest campaign board game of all time is finally available for the PC. Can my old heart stand the strain?