Claimer: Sorry this was rushed but I will try to go into as much detail as I can.
Defensively:
Ian ppp 0.85 fg% 40.2
%Time
7% Isolation 0.78 ppp
45% Post up 0.95 ppp
25.6% PnR roll man 0.82 ppp
17.8% Spot up 0.65 ppp
Rim protection via sportsvu fg% 43%
Andrew Bynum 0.77 ppp fg% 36.5%
%Time
13.6% Isolation 0.67 ppp
28.4% post up 0.64 ppp
27.3% PnR roll man 0.58 ppp
27.3% Spot up 1.13 ppp
Rim protection via sportsvu fg% 37.6%
So the glaring weakness in Bynums defense is his spot up defense. I haven't look hard at it but my guess is that he doesn't close out nearly as well as Ian but he also may just concede that shot more often to protect the paint where he sees less attempts at the rim per game than Ian and does a pretty good job at defending the rim as well.
Their perecentage of shooting fouls are about the same at around 7%.
The suprises to me are the highlighted in red and specifically the PnR defense of Bynum. Giving up 0.58 ppp is absurd and I need to look further into it and see what kind of help defense he was getting but it was most likely the typical ICE play we run with Ian.
Offensively:
I need more time but I will point out two things that probably many of you already have noticed.
Ian is a turnover machine at 20.8% while Bynum is a modest 11.3% per possession
Ian's offensive ppp is 0.75.
Bynums offensive ppp is 0.82.
The largest disparity in offensive plays is Bynum post up 58.9% to Ians 8.1%. Bynum on post ups ppp is 0.75, Ians is 0.5 ppp with a eye popping 18.2% field goal percentage.
Ian is the much better roll man on the pnr as you would expect as well as a better cutter to the basket. This is where he makes up his efficiency.
Bynum however is much better at getting to the free throw line and like I said he doesn't turn the ball over on a fifth of his possessions.
As for offensive rebounds Bynum is also better and he is also better at passing the ball.
Like many of you have said if Bynum finds his offensive mojo then this will be a slam dunk signing all things considered.
I think its obvious we got an upgrade for the backup center spot.