Sue for what?
In any case, what difference would that make? FIFA suing UEFA wouldn't have any bearing on Germany etc... leaving FIFA. In fact, it may do further good in terms of dragging UEFA down with FIFA and Platini down with Blatter.
I don't understand what difference that makes to the possibility of the UEFA teams leaving FIFA?
It would simply mean that they wouldn't play in the FIFA World Cup or any other FIFA competitions. :shrug: