Here's some starter questions, but don't limit yourself:
1) What was helpful/useful in FM 3-24?
2) What is missing in FM 3-24?
3) What needs amplification?
4) What needs de-emphasis?
5) What is flat wrong or needs removal?
6) Does the manual strike the balance between specific, applicable knowledge and theory of operations?
7) How does the manual hold up in application in Iraq/Afghanistan, and does its principles hold up outside of Iraq/Afghanistan?
Join the discussion at Small Wars Council - Revising FM 3-24: What needs to change?