OMG! That is very limiting, is isn't? So its better to have a single battery for each light than to work at the mercy of a single battery. The Digital RX pack system is not limited in this way, correct?
You do realize to be able to have a non fixed ratio you would need to have two batteries in one unit, along with two sets of powercontrols. (just as the RX powerpack has)
To change the ratio you can change the distance to the subject of lights of course. (thats where the extension cables comes handy)
A 2:1 ratio setup is actually quite common in portraiture so its more a feature then a limitation. 
But yes if you want to control alot of lights on location with diffrent ratios you need alot of Rangers. 


