I'm sure most of these are already in the "what I presume to be massive" suggestion box, but I thought I'd throw them out anyway:
1. Family.ObjectName( Event/Expression) - Get the project-defined name of an object within a picked family list. If current Family SOL list is greater than one, it does the standard Construct 2 behavior which just returns the ObjectName of the first one in the currently picked Family set.
2. Clone object (Action) - Copies all instance variables, position, etc. The only things that would be new would be UID and IID values.
3. IsBehaviorActive (Event/Expression) - We can already disable/enable behaviors through events, it would be nice to also have a Platform.IsBehaviorEnabled/Bullet.IsBehaviorEnabled/etc (it would help save having to declare an instance variable)
4. Sprite.HasAnimation(string animName) - Expression/Action - returns true/false as to whether an animation of some name exists for a given sprite. This would be an incredibly useful since I am frequently adding sprites with specific sets of animation names and have generic code to handle switching between them.
And lastly I wish to impart my sincere appreciation for the work and care that has gone into Construct 2 in the first place!