I have been waiting for this since the first version of Medal of Honor.
I basically saw it as a grid of maps (regardless of there being any historical reason to link them), some urban, some countryside, etc.
You started with Map A, if the attacker wins, you move on to Map B, if they win that, move to C, if they lose, move back to A, with the roles of attacker and defender reversed (if possible). Pretty simple really.
If the roles cannot be reversed than a similar map could be substituted that allows for the attacker/defender roles to be correct.
It could be more complex, but does not have to be. But ideas included.
* Win Map B and have a choice of more than one map, i.e. more than one route on the master map. This could be limited to only certain "crossroads" maps or all maps on the grid could have an attacker's choice available.
* Have a master number of total troops available for the whole match, not just each map. If the defender holds out long enough they get extra reinforcements. If the attacker wins fast enough they get a bonus.
Would be a blast, particularly for clan matches.
It was one of the reasons I decided to by RO2 and one of the major disappointments when it failed to appear.
I look forward to the day it arrives.
If it is anything like the idea above, like a master map made up of sections or smaller maps, It would be WONDERFUL if the servers could pick whatever maps they wanted to - even if it were unhistorical and could include maps made by modders.