Re: How many years should WB wait before making a Batman reboot?
Exactly; the character's history is way too rich and diverse to be limited by any singular vision. Otherwise it becomes old hat and something that people no longer care for due to it outdoing it's welcome.
This is something that will still be around when many of us are dead. The comics have endured because of constant reinventions and reinterpretations every decade since the 1939 debut. The addition of new elements to the mythos through all of those different eras has helped Batman sustain himself as a large element of pop culture. The same should apply to any other form of media using the same foundations.
As for the poll question; I personally think 5-6 yrs is not only the most realistic option on there but also probably the healthiest one. It gives it enough distance from the previous iteration to have it's own space and also enough time to be redefined for a new generation of movie goers.
Pull list: Saga, Teenage Mutant Ninja Turtles, Justice League, Earth 2, Multiversity, Daredevil, All-New X-Men