I'm not keeping track of minutes or anything, but the fact that it's happened
at all is damning enough I'd say. Starting off the 4th quarter with extreme small-ball even if it only lasts for 4 minutes has been enough to completely take us out of games on several occasions. What do we really gain by having Collison and Rondo playing together? Collison tends to be overly-aggressive about forcing shots which aren't there as he seems to believe he's out there to be our closer or something even though he's not very good at it. He's a facilitator not a scorer. The more shots he forces up the less effective he is. Rondo becomes extremely passive on offense too in that lineup at which point there's no reason to even have him on the court because he's a liability defensively unless he's face guarding the other team's PG and even with the improved jumper he's not a guy you want to feed the ball to spotted up behind the arc.
Our guards are getting killed primarily in the late third to early fourth quarter of games which is precisely when Karl is playing the Rondo/Collison/Belinelli (and sometimes Seth) lineup. When it's just Ben and Rajon we're fine. Darren or Seth at PG are fine. Playing 2 or 3 PGs at once is a problem. Marco is a problem and he's not even hitting his shots consistently enough to justify the amount of run Karl gives him in the second half.
As for your rhetorical question about the Marco/Ben conundrum -- I think the production speaks for itself. Marco is averaging 4 more points per game on
40% shooting to Ben's 46%. That's the definition of a chucker. Do I really want a 37% three-point shooter taking those shots over a 33% shooter? Hell yes I do. And since he's also a better defender and doesn't chuck up crap or dribble into traps and jump-pass the ball to the other team it should be a no-brainer. I know Marco has been a consistent shooter in the past but he's taking almost exclusively low-percentage shots this season when Rondo isn't spoon-feeding him. The only advantage he has over Ben is the ability to set up other players but there's no way the trade-off is worth it. Putting the ball in Rondo's hands instead of the hybrid Darren/Marco attack means you don't need another ball-handler in the back court and frankly, DeMarcus is doing a fine job of spacing the floor on his own right now.
I can't overstate how much I hate the way George Karl is managing the fourth quarter this season. Every game I watch I feel like I'm about to have an aneurysm. Maybe to you that reads as some kind of hell-bent anti-Karl crusade but honestly, I'm just that pissed off about it. I could say a whole lot more than I am, I'm just trying to restrain myself. It gets to a point where I just can't hold it back anymore. Especially when I keep reading comments from other people pointing the finger in the wrong direction (Cousins is a cancer, Rondo is a stat-stuffer and net-detriment, Rudy is a lazy bum, Ben is a scared little pup, et al). It's all insanity as far as I'm concerned. Here's what makes sense to me: Play these guys at their natural positions, stop relying on Darren and Marco to run the offense in the fourth quarter, keep a shot blocker on the court at all times. If we don't switch our guards onto the other team's scoring bigs than we won't have to double them all the time and leave shooters wide open. This stuff is all basketball 101.
I don't put much stock into what George Karl says he wants to do anymore because his actions tell a different story. He had plenty of WCS early in the season and he stayed rooted to the bench in the 4th quarter with Ben. I make no bones about openly pining for an old-school coach like
this guy who'll cut the nonsense and just teach solid fundamental basketball.