Last year the Bulldogs forward pack threw more passes (not offloads) than any other side in the competition and the Roosters just bumped the ball up the middle. The Roosters were the best defensive side in the league and the Dogs were the worst of all the top 8 sides. Wayne Bennett once said that Rugby League is a simple game...tackle hard, run hard and hold onto the ball.
I can see your angle and I certainly agree that attack has some bearing on defence, but I share the opinion of top NRL coaches that constantly harp on about getting the defence right, and the rest will take care of itself.
Using the Bulldogs is a poor example, first of all their halves are average at best, their forwards for most of the last few years and even this year are on the slow fat lumbering side and their ball movement between the forwards has basically been the same the last few years (second man interchange plays to draw in the middle edges to suck the centres in early----which has been tweaked a little offering more first man lead flat plays as an option)
Comparing the variety of ball playing options the Bulldogs have to move the defence around to what Manly have had in the past the Bulldogs have basically low quality options.(Foran one side and through the middle DCE, Glenn Stewart, Lyon on the other along with improved ballplaying through the forwards is more varied than what the Dogs have to offer)
How Manly turned Melb inside out in the 08 GF showed the way for many other clubs to tackle the wrestle and gang tackle effectiveness of Melb along with adding size and grunt.
The teams of the last few years who have added the right mix of explosive punch and simple direct plays have improved their attacking output without even having to be overly creative in attack taking pressure off the halves and generating space out wide when required.
The consistent direct go forward helped in establishing good field position at the end of each set and more likely to dominate the first two tackles in defence in a more dominant field position.
The Cowboys improved their go forward with more simple direct punch, better drilled than the past along with the attack plus defence benefited off this good platform---confidence breeds confidence in all areas.
Remove one or two quality power forwards from the depth of a club and you come back to the field real fast if you don't have expansive creative ball playing go forward structures.(See Roosters and Souths last year----yes a drop in attitude especially with Souths did not help either)
Tony Williams when he first entered first grade on the wing had the right physique to be a power forward, now he is a fat lazy lumbering type more and more each day. Combine the above with his soft overall attitude and you have a waste of size that the Bulldogs paid overs for---they have too many forwards with the wrong physique.
Manly suffered the same under Hasler more so in some years than others(getting run down often was evidence of this) only our expansive ball playing each set and our quality backline covered up our poor forward depth for the most part.
Consistent punch in go forward and smart aggression in defence is the key platform to work off and if the attitude is right the defence will follow, only needing good structures and technique to tweak the last 20% of improvements.
Under Hasler Manly had explosive moments especially after stoppages of play or at the start of each half where Manly raised the intensity in the hope of generating a good return with points scoring quickly then revert back to the grind once we would inevitably fatigue.(good attitude under high fatigue is what set us apart and kept our defence in good order but we were right on the edge of hitting the wall if things did not go our way)