I actually I have a lot more to say on how the OFFENSE has completely deteriorated over the last couple decades.
To comment on the subject at hand, I don't think the rules changes are affecting the defensive side of the ball too much. You always hate to see a bunch of ticky tack fouls called but even in that horrible scenario, its MUCH WORST when the refs aren't consistent. The "star" factor that rears its ugly little head with most of these non-existent/inconsistent ticky tack fouls is also quite a bother. Gilbert Arenas scored 30 POINTS!!,....yeah 18 of them were free throws. And I think that sad institution compromises the effectiveness of a well-prepared defensive team moreso than a "hand-check" rule.
Offensively is where things truly have gone into the crapper. And I'll blame Michael Jordan as much as the next guy but I think coaches have to share the blame also. I think that there is a lot of pressure on coaches to show that they are 'tangibly' affecting the success of their teams. So they succumb to the pressures and start micro-managing as much of the movement (on the ball and off the ball) of all 5 guys on the floor, as possible. "Well, that there dude sure knows how ta coach, yessiree!"
People like to talk about the brilliant basketball mind of Mike D'Antoni. The guy pretty much took a page out of Pre-Iso basketball. Here's the gist: get a rebound, give it to your point, let him push as fast as he can, penetrate, dish to the open man, SHOOT, done. I don't care if that open man is Eddie House, Boris Diaw, James Jones, Shawn Marion, Quentin Richardson, Joe Johnson, Jim Jackson, or Leandro Barbosa. If the team made the previous shot or the team got back on D, walk it up--screen and roll, DONE! I mean its so simple a junior high team could do it.
Nope, nowadays people have to be geniuses like Larry Brown, Rick Carlisle, Eddie Jordan, Pat Riley, Phil Jackson -- Triangle offenses, Rectangular Trapezoidal offenses but if your not into geometry its a Princeton offense, Stanford offense, Dartmouth offense, <insert Ivy league school here> offense.........its a bunch of Bull Hockey and some people are starting to look like idiots having their players run around like chickens with their heads cut off on the way to another 24 second violation.