weight paint behaving like vertex paint

On a model I been working on, I had just finished the armature. Now all that is left is the weight paint. Before I continue this is a minecraft character. The weight paint is only working on the 4 vertices on each part.

Now on other models it did not appear to do this. All the models I have worked on were rather low poly aside from 1 sculpture. All of which allowed me to weight paint the same as though i was in texture mode. So whats going on?

My guess is that the old model had subsurf enabled with the modifier set before the armature modifier, and the new ones don’t have a subsurf modifier or have it after the armature.