Raphael
You say that "God is hoping David would take responsibility for his sin - David doesn't - he fails to show hearfelt repentence - all he would need to do in order for God to turn from bringing judgement upon himself and the nation."
In fact David did exactly that; v10 And David’s heart began to beat him after he had so numbered the people. Consequently David said to Jehovah: "I have sinned very much in what I have done. And now, Jehovah, let your servant’s error pass by, please; for I have acted very foolishly."
Nicolaou...
It is true David does feel guilty and admit his sin , asks for forgiveness ...However is it true heartfelt repentance . I would suggest that David does not realize the full impact of his actions -
I think it is also important to note that the census took place over a period of almost 9 months , before God chose to act - giving David sufficient time in which to change course.
In verses 12-13 God gives David 3 choices to test his heart...
Two of the choices involve situations that would effect the nation as a whole :
Famine would not neccessarily effect David and his family .As the Royal family we could argue that their needs would be met, famine would largely effect the most vulnerable in the nation.
The option of disease would also expose the most vulnerable and afflict the entire nation - David and his household it could be argued would have the resources to temporarily flee and so escape the situation.
My guess is that if David had chosen the option to be pursued by his enemies - this choice would perhaps indicate that he was taking full responsibilty for his sin..
Notice how God words this choice "...or will YOUR enemies chase YOU and make YOU run from tehm for 3 MONTHS...
Verse 14 tells us David was really frightened, and leaves his and the nations fate in God hands.
As I mentioned previously David seemingly fails to take full responsibilty - possibly an indication of a lack of heartfelt repentance.
God chooses and the entire nation suffer as a result ...
Verse 17 David finally realises the full impact of his sin he now takes responsibility and says in effect the nation have not sinned ..it is me who has lead them astray as leader punish ME and MY family...
God halts the slaying ...and the plague ends...
Interesting to note that in the verses that follow , David also produces works that befit repentance , by offfering sacrifices in accordance with Mosaic Law - thus making atonement for the sin .
God is vindicated as a righteous judge.