The bigger problem with White Peace to me seems - as with everything else - that the AI doesn't do anything unless it's absolutely forced to. In this case, waiting for 100 WE.
I'm not saying it's awesome at this in EU, but at least it occasionally calls for a White Peace if it doesn't make any gains. So, in my current game, an AI called me into a war, and I thought, sure, have fun, let's see what you are doing - but again they aren't doing anything - and I can't get there to put anyone out of their misery either. Which is obnoxious, as out of sheer boredom I thought I'd start a Federation, but, oops, not possible while being at war ...
A few decades later ...
WE at 50%, still nothing happened, still waiting. Ach, the fun we are having ^^