I agree that we're a bit limited upfront and that Atlanta and Cleveland's size did present some problems. However, as some have already pointed out, who is really the answer to that? It's not like there's a lot of great big man out there to begin with, particularly not ones who are going to sign for the MLE.
I think Perkins and Rondo learning to finish around the basket against athletic big men would go a long way in helping us too. It always kills me when Perkins dribbles it once before he goes up for a dunk. It's stupid things like that more than size that hurt us against the Hawks and Cavs.
I also wouldn't worry too much about Bynum. He hasn't proved anything yet and we don't know how well he's going to bounce back from his injuries. Furthermore, I'm curious to see if the Lakers can function with him. Unless they trade Odom for Artest or something like that, what used to be a very quick team becomes rather slow with Bynum at the 5 and Odom at the 3. Furthermore, while Bynum could help with interior defense, Odom and Gasol are matadors. Plus, how's all of this going to work with the triangle, none of L.A.'s frontcourt can shoot. To me, this seems an awful lot like the Rockets team with Olajuwon, Barkley, and Pippen. It sounds good on paper, but there games really didn't compliment each other. I foresee Bynum's presence hindering Kobe and Gasol as he clogs the lane both defensively and offensively. As bad as I think Radmanovic is, I think their offense isn't going to run smoothly without a shooter like him on the floor. And if their offense weakens, whatever help Bynum can give defensively isn't going to make up for that. so I wouldn't assume we definitely see the Lakers back in the Finals again next year.
All in all, I agree we could use some frontcourt help, but that's easier said than done. And whatever center we could get for the MLE won't be good enough to make up for Posey.