DBP is designed to make games. When DBP was used to produced a game engine, the programmer had to deal with a new set of chalenges. The engine had to read a structure created by another software ( the editor ) which led I think to some of the problems we are facing, such as the culling ( or lack of ) discussed on the Riker 9 thread.
It has nothing to do with DBP per se or Lee's ability. I think both are state of the art in their own context. The main issue here was stretching DBPs line to another completely diferent environment such as creating a game making software starting from a language that is already a game making software.
Even if there are a lot of aspects I think should be dealt with, look at it: it's an enormous ammount of work to pull such a stunt.
I'm pretty sure I know everything. Doubts are something rare in me and I am never wrong, as this signature can prove.