[mtbcoder]

> The only part of the presentation layer that WordPress needs to concern itself with is the admin interface.

If only this were the case. WP's underlying processes and database structure are so unbelievably stunted and entirely coupled to the core WP application, that to do something as simple as pull rendered posts from the database generally involves performing a series of SQL gymnastics just to retrieve the relevant data. Not to mention all of the convoluted WP functions that are needed to render the final content snippet.

[mikeschinkel]

There are pros and cons to WordPress' database structure. While it may take "a series of SQL gymnastics just to retrieve the relevant data" it's database structure is incredibly resilient to the changing requirements of different users. A "better" database structure would almost certainly be too fragile to meet the needs of as many users as WordPress does.