This non-instantaneous battle idea have been well discussed already in the topic Anjire gave a link to.
Would be quite an ineresting improvement... but as battles take time, it brings a real issue imo: it's about diplomatic relations between amies. Imagine player A defends a spot with large armies, Player B who has no Diplo relations with A can attack him. Player C is in Confed/NAP with A and B but decides to help A defend for exemple... here there's an issue because with current diplo mechanics, he can help none.
If Devs are willing to make some PVP battles non-instantaneous, the diplomatic relations system should be first reworked to avoid incoherences. Like someone in a goup of confeds can't be as well in NAP/Confed with an enemy his group is at war with. Currently, to take the exemple of the current war, any Consone alliance could be confed with H? or Dlords while still confed with the rest of Consone.
In the interaction exemple i gave, it's a hard case as B has no relations with A, and C is Confed with A and B. As B attacked A one solution would be to automatically change diplo status of B with C from confed to without relation or War. Same way, C could have an option to chose to defend A or to attack A, which would be seen as a betrail for B or A and change his diplo status automatically.
Though, this means 1 player would make his whole alliance change automatically diplomatic status with an other alliance, if he supports one or the other side. And here it's an exemple with 3 players from 3 different alliances... sounds like a nightmare if more alliances with various diplo relations fight on a same spot.
An other idea though, would be to let alliances change their diplo status first, before being able to do anything. In my exemple, alliance of player C could first manually change its relation with B from Confed to War/no-relation in order to let player C help player A. But here the interaction exemple is just between 3 alliances... how does it work between more alliances battling on a same spot, and with various diplo intereactions?
I personnally think non-instantaneous battles would need to first re-view the current diplomatic relations system (which has to be re-viewed anyway, imo), it wouldn't work with the current one.
Edited by Mandarins31 - 12 Jan 2013 at 10:24