-As I asked last week, how compatible will old published material be with 5E? As Philo Pharynx pointed out in the comments, WotC has already declared ascending AC will be how AC is done, thus excluding most 1E material. Now I ask, how close to compatible with old published material will 5E need to be? For myself, I can handle changing AC on the fly, as long as I do not also have to change hp, damage, and other such "basic" components of a monster/module.
The real question for me is...will converting an old published module require me to do it before the adventure is run or can I do it on the fly? I want to feel that I can use my older material with 5E.
At the very least WotC should include a conversion methodology for each former edition of D&D to 5E, instead of only converting from 4E to 5E.
Now I ask you, how much would it take in conversion before you feel you can no longer do it on the fly?